GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2025-39682 (GCVE-0-2025-39682)

Vulnerability from cvelistv5 – Published: 2025-09-05 17:20 – Updated: 2026-09-19 03:56
VLAI CISA Previdian
Title
tls: fix handling of zero-length records on the rx_list
Summary
In the Linux kernel, the following vulnerability has been resolved: tls: fix handling of zero-length records on the rx_list Each recvmsg() call must process either - only contiguous DATA records (any number of them) - one non-DATA record If the next record has different type than what has already been processed we break out of the main processing loop. If the record has already been decrypted (which may be the case for TLS 1.3 where we don't know type until decryption) we queue the pending record to the rx_list. Next recvmsg() will pick it up from there. Queuing the skb to rx_list after zero-copy decrypt is not possible, since in that case we decrypted directly to the user space buffer, and we don't have an skb to queue (darg.skb points to the ciphertext skb for access to metadata like length). Only data records are allowed zero-copy, and we break the processing loop after each non-data record. So we should never zero-copy and then find out that the record type has changed. The corner case we missed is when the initial record comes from rx_list, and it's zero length.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: active Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-18 00:00 UTC
CWE
  • CWE-754 - Improper Check for Unusual or Exceptional Conditions
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < 2902c3ebcca52ca845c03182000e8d71d3a5196f (git)
Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677 (git)
Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < 3439c15ae91a517cf3c650ea15a8987699416ad9 (git)
Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < 29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e (git)
Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < 62708b9452f8eb77513115b17c4f8d1a22ebf843 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.0
Unaffected: 0 , < 6.0 (semver)
Unaffected: 6.1.149 , ≤ 6.1.* (semver)
Unaffected: 6.6.103 , ≤ 6.6.* (semver)
Unaffected: 6.12.44 , ≤ 6.12.* (semver)
Unaffected: 6.16.4 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Siemens SIMATIC CN 4100 Affected: 0 , < V5.0 (custom)
guessed Create a notification for this product.
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 61617b0a-4c8f-4424-9587-02d63af5a527

Vulnerability ID: CVE-2025-39682

Status: Confirmed

Status Updated: 2026-09-18 00:00 UTC

Exploited: Yes

Timestamps
First Seen: 2026-09-18
Asserted: 2026-09-18
Scope
Notes: Linux Kernel Improper Check for Unusual or Exceptional Conditions Vulnerability | Affected: Linux / Kernel | Description: Linux Kernel contains an improper check for unusual or exceptional conditions vulnerability in the TLS receive path which allows a zero-length record retrieved from the rx_list to bypass the intended recvmsg() record-type handling, potentially causing subsequent TLS records to be processed using incorrect zero-copy and queuing assumptions. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version. | Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. | Due date: 2026-09-21 | Known ransomware campaign use (KEV): Unknown | Notes (KEV): This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: ; https://git.kernel.org/stable/c/2902c3ebcca52ca845c03182000e8d71d3a5196f; https://git.kernel.org/stable/c/c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677; https://git.kernel.org/stable/c/3439c15ae91a517cf3c650ea15a8987699416ad9; https://git.kernel.org/stable/c/29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e; https://git.kernel.org/stable/c/62708b9452f8eb77513115b17c4f8d1a22ebf843 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2025-39682
Evidence

Type: Vendor Report

Signal: Successful Exploitation

Confidence: 80%

Source: cisa-kev

Details
Cwes CWE-754
Feed CISA Known Exploited Vulnerabilities Catalog
Product Kernel
Due Date 2026-09-21
Date Added 2026-09-18
Vendorproject Linux
Vulnerabilityname Linux Kernel Improper Check for Unusual or Exceptional Conditions Vulnerability
Knownransomwarecampaignuse Unknown
References
Created: 2026-09-18 20:00 UTC | Updated: 2026-09-18 20:00 UTC
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 21f76e95-2fa4-464b-b0be-ef2fc48d5693

Vulnerability ID: CVE-2025-39682

Status: Confirmed

Status Updated: 2026-09-18 19:20 UTC

Exploited: Yes

Timestamps
First Seen: 2026-09-18
Asserted: 2026-09-18
Scope
Notes: tls: fix handling of zero-length records on the rx_list | Affected: Linux / Linux | CVSS: 9.8 (CRITICAL) | EPSS: 0.00505 | Used in malware: unknown | Not yet in CISA KEV: False
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: previdian

Details
Feed Previdian (previdian.com)
Title tls: fix handling of zero-length records on the rx_list
Cve Id CVE-2025-39682
Vendor Linux
Ghsa Id GHSA-V2PF-75PF-9C5H
Product Linux
Added Date 2026-09-18T19:20:38.811Z
Cvss Score 9.8
Epss Score 0.00505
Previous Ids
Cvss Severity CRITICAL
Virtual Patch False
Cvss Estimated False
Epss Percentile 0.42129
Used In Malware unknown
Vulnerability Id CVE-2025-39682
Ahead Of Cisa Kev None
Not Yet In Cisa Kev False
References
Created: 2026-09-19 20:00 UTC | Updated: 2026-09-19 20:00 UTC
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T17:42:13.673Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "affected": [
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC CN 4100",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "V5.0",
                "status": "affected",
                "version": "0",
                "versionType": "custom"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-12T12:06:08.852Z",
          "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
          "shortName": "siemens-SADP"
        },
        "references": [
          {
            "url": "https://cert-portal.siemens.com/productcert/html/ssa-032379.html"
          }
        ],
        "x_adpType": "supplier"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-39682",
                "options": [
                  {
                    "Exploitation": "active"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-18T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-754",
                "description": "CWE-754 Improper Check for Unusual or Exceptional Conditions",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-19T03:56:24.457Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "government-resource"
            ],
            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-39682"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/tls/tls_sw.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2902c3ebcca52ca845c03182000e8d71d3a5196f",
              "status": "affected",
              "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
              "versionType": "git"
            },
            {
              "lessThan": "c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677",
              "status": "affected",
              "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
              "versionType": "git"
            },
            {
              "lessThan": "3439c15ae91a517cf3c650ea15a8987699416ad9",
              "status": "affected",
              "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
              "versionType": "git"
            },
            {
              "lessThan": "29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e",
              "status": "affected",
              "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
              "versionType": "git"
            },
            {
              "lessThan": "62708b9452f8eb77513115b17c4f8d1a22ebf843",
              "status": "affected",
              "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/tls/tls_sw.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "lessThan": "6.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.149",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.103",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.44",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.149",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.103",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.44",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16.4",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntls: fix handling of zero-length records on the rx_list\n\nEach recvmsg() call must process either\n - only contiguous DATA records (any number of them)\n - one non-DATA record\n\nIf the next record has different type than what has already been\nprocessed we break out of the main processing loop. If the record\nhas already been decrypted (which may be the case for TLS 1.3 where\nwe don\u0027t know type until decryption) we queue the pending record\nto the rx_list. Next recvmsg() will pick it up from there.\n\nQueuing the skb to rx_list after zero-copy decrypt is not possible,\nsince in that case we decrypted directly to the user space buffer,\nand we don\u0027t have an skb to queue (darg.skb points to the ciphertext\nskb for access to metadata like length).\n\nOnly data records are allowed zero-copy, and we break the processing\nloop after each non-data record. So we should never zero-copy and\nthen find out that the record type has changed. The corner case\nwe missed is when the initial record comes from rx_list, and it\u0027s\nzero length."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is triggered entirely by the sequence and content of TLS records arriving from the remote peer on a kTLS-enabled TCP socket (net/tls RX path); no local access is needed. Any kTLS RX consumer \u2014 OpenSSL-with-kTLS servers/clients, NFS-over-TLS, SMB/RPC-over-TLS via net/handshake \u2014 is remotely reachable over the network.\nAC:L - The attacker sends three back-to-back records ([DATA][zero-length non-DATA][DATA]) and the corruption occurs deterministically on the victim\u0027s ordinary recvmsg() loop, with no race to win and no memory-layout dependency; the kernel selftest added with the fix reproduces it in one shot. TLS 1.2 is zero-copy-capable by default (zc_capable = rx_no_pad || version != TLS_1_3_VERSION), so no unusual kernel config or sockopt is required.\nPR:N - The attacker is the remote TLS peer, which holds no privileges on the target system \u2014 an anonymous client completing a server-authenticated TLS handshake with a kTLS server, or a malicious server that a kTLS client connects to, suffices. This matches the repo\u0027s PR:N scoring of the comparable remote-peer net/tls bug CVE-2025-39946.\nUI:N - The victim application only has to run its normal recvmsg() loop on an already-established kTLS socket; no click, mount, file open, or any other victim action is required. The attacker drives the entire trigger from the wire.\nS:U - The corruption is confined to kernel skb/slab state within the same security authority; there is no VM, IOMMU, or sandbox boundary crossed. Standard in-kernel memory corruption is Scope:Unchanged.\nC:H - The strparser anchor is queued on rx_list after tcp_read_done() already released its backing TCP skbs, so the next recvmsg() copies freed kernel heap memory straight into the userspace buffer via skb_copy_datagram_msg(). This is a directly usable, repeatable kernel-memory disclosure primitive, not a bounded pointer leak.\nI:H - The live strp-\u003eanchor is consume_skb()\u0027d by process_rx_list() while the strparser still uses it, after which incoming attacker-controlled TCP data is written into the freed sk_buff/skb_shared_info (skb_fill_page_desc, tls_strp_load_anchor_with_queue), and socket teardown double-frees the anchor and its frag_list skbs. This yields attacker-controlled write-after-free and freelist corruption suitable for control-flow hijack.\nA:H - The use-after-free and double-free of the anchor and of already-released TCP receive-queue skbs reliably corrupt slab state, producing oopses/panics and list corruption. Any remote peer can repeat this on every connection, giving a trivial remote kernel-crash DoS."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:04:31.384Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2902c3ebcca52ca845c03182000e8d71d3a5196f"
        },
        {
          "url": "https://git.kernel.org/stable/c/c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677"
        },
        {
          "url": "https://git.kernel.org/stable/c/3439c15ae91a517cf3c650ea15a8987699416ad9"
        },
        {
          "url": "https://git.kernel.org/stable/c/29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e"
        },
        {
          "url": "https://git.kernel.org/stable/c/62708b9452f8eb77513115b17c4f8d1a22ebf843"
        }
      ],
      "title": "tls: fix handling of zero-length records on the rx_list",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-39682",
    "datePublished": "2025-09-05T17:20:48.657Z",
    "dateReserved": "2025-04-16T07:20:57.113Z",
    "dateUpdated": "2026-09-19T03:56:24.457Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-39682",
      "date": "2026-09-20",
      "epss": "0.012",
      "percentile": "0.66798"
    },
    "microsoft_vex": {
      "current_release_date": "2025-09-07T01:10:35.000Z",
      "cve": "CVE-2025-39682",
      "id": "msrc_CVE-2025-39682",
      "initial_release_date": "2025-09-02T00:00:00.000Z",
      "product_status:fixed": "1",
      "product_status:known_affected": "2",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "tls: fix handling of zero-length records on the rx_list",
      "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-39682.json",
      "version": "1"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/tls/tls_sw.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "2902c3ebcca52ca845c03182000e8d71d3a5196f",
                    "status": "affected",
                    "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677",
                    "status": "affected",
                    "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "3439c15ae91a517cf3c650ea15a8987699416ad9",
                    "status": "affected",
                    "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e",
                    "status": "affected",
                    "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "62708b9452f8eb77513115b17c4f8d1a22ebf843",
                    "status": "affected",
                    "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/tls/tls_sw.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.0"
                  },
                  {
                    "lessThan": "6.0",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.149",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.103",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.44",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.16.*",
                    "status": "unaffected",
                    "version": "6.16.4",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.17",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          },
          {
            "affectedData": [
              {
                "defaultStatus": "unknown",
                "product": "SIMATIC CN 4100",
                "vendor": "Siemens",
                "versions": [
                  {
                    "lessThan": "V5.0",
                    "status": "affected",
                    "version": "0",
                    "versionType": "custom"
                  }
                ]
              }
            ],
            "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
          }
        ],
        "cisaActionDue": "2026-09-21",
        "cisaExploitAdd": "2026-09-18",
        "cisaRequiredAction": "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA\u2019s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA\u2019s \u201cForensics Triage Requirements\u201d (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset\u0027s internet exposure and ensuring adherence to BOD 26-04 patching guidelines.",
        "cisaVulnerabilityName": "Linux Kernel Improper Check for Unusual or Exceptional Conditions Vulnerability",
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "DE30211F-1A6B-457E-B19D-D3E385550199",
                    "versionEndExcluding": "6.1.149",
                    "versionStartIncluding": "6.0",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "F2293654-7169-49B5-8D0D-EE51EF8B8E48",
                    "versionEndExcluding": "6.6.103",
                    "versionStartIncluding": "6.2",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "12351F24-1133-4775-960C-F2B47E81298B",
                    "versionEndExcluding": "6.12.44",
                    "versionStartIncluding": "6.7",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "AFC28995-B8C3-4B68-8CB6-78E792B6629D",
                    "versionEndExcluding": "6.16.4",
                    "versionStartIncluding": "6.13",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "327D22EF-390B-454C-BD31-2ED23C998A1C",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "C730CD9A-D969-4A8E-9522-162AAF7C0EE9",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          },
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*",
                    "matchCriteriaId": "FA6FEEC2-9F11-4643-8827-749718254FED",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntls: fix handling of zero-length records on the rx_list\n\nEach recvmsg() call must process either\n - only contiguous DATA records (any number of them)\n - one non-DATA record\n\nIf the next record has different type than what has already been\nprocessed we break out of the main processing loop. If the record\nhas already been decrypted (which may be the case for TLS 1.3 where\nwe don\u0027t know type until decryption) we queue the pending record\nto the rx_list. Next recvmsg() will pick it up from there.\n\nQueuing the skb to rx_list after zero-copy decrypt is not possible,\nsince in that case we decrypted directly to the user space buffer,\nand we don\u0027t have an skb to queue (darg.skb points to the ciphertext\nskb for access to metadata like length).\n\nOnly data records are allowed zero-copy, and we break the processing\nloop after each non-data record. So we should never zero-copy and\nthen find out that the record type has changed. The corner case\nwe missed is when the initial record comes from rx_list, and it\u0027s\nzero length."
          }
        ],
        "id": "CVE-2025-39682",
        "lastModified": "2026-09-19T04:17:35.263",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.2,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2025-39682",
                "options": [
                  {
                    "exploitation": "active"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-18T00:00:00+00:00",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2025-09-05T18:15:44.670",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/2902c3ebcca52ca845c03182000e8d71d3a5196f"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/3439c15ae91a517cf3c650ea15a8987699416ad9"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/62708b9452f8eb77513115b17c4f8d1a22ebf843"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Mailing List",
              "Third Party Advisory"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
          },
          {
            "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
            "url": "https://cert-portal.siemens.com/productcert/html/ssa-032379.html"
          },
          {
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-39682"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Undergoing Analysis",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "NVD-CWE-Other"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          },
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-754"
              }
            ],
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-19T02:00:15+00:00",
      "cve": "CVE-2025-39682",
      "id": "CVE-2025-39682",
      "initial_release_date": "2025-09-05T00:00:00+00:00",
      "product_status:fixed": "1092",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: tls: fix handling of zero-length records on the rx_list",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39682.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-20T00:09:04Z",
      "cve": "CVE-2025-39682",
      "id": "CVE-2025-39682",
      "initial_release_date": "2025-09-08T23:22:54Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "397",
      "product_status:known_not_affected": "390",
      "product_status:recommended": "573",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-39682",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-39682.json",
      "version": "58"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2025-11-03T17:42:13.673Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "affected": [
              {
                "defaultStatus": "unknown",
                "product": "SIMATIC CN 4100",
                "vendor": "Siemens",
                "versions": [
                  {
                    "lessThan": "V5.0",
                    "status": "affected",
                    "version": "0",
                    "versionType": "custom"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-05-12T12:06:08.852Z",
              "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
              "shortName": "siemens-SADP"
            },
            "references": [
              {
                "url": "https://cert-portal.siemens.com/productcert/html/ssa-032379.html"
              }
            ],
            "x_adpType": "supplier"
          },
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2025-39682",
                    "options": [
                      {
                        "Exploitation": "active"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-09-18T19:25:58.427206Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-754",
                    "description": "CWE-754 Improper Check for Unusual or Exceptional Conditions",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-06-11T17:39:04.325Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "references": [
              {
                "tags": [
                  "government-resource"
                ],
                "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-39682"
              }
            ],
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "net/tls/tls_sw.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "2902c3ebcca52ca845c03182000e8d71d3a5196f",
                  "status": "affected",
                  "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                  "versionType": "git"
                },
                {
                  "lessThan": "c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677",
                  "status": "affected",
                  "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                  "versionType": "git"
                },
                {
                  "lessThan": "3439c15ae91a517cf3c650ea15a8987699416ad9",
                  "status": "affected",
                  "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                  "versionType": "git"
                },
                {
                  "lessThan": "29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e",
                  "status": "affected",
                  "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                  "versionType": "git"
                },
                {
                  "lessThan": "62708b9452f8eb77513115b17c4f8d1a22ebf843",
                  "status": "affected",
                  "version": "84c61fe1a75b4255df1e1e7c054c9e6d048da417",
                  "versionType": "git"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "net/tls/tls_sw.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "6.0"
                },
                {
                  "lessThan": "6.0",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.1.*",
                  "status": "unaffected",
                  "version": "6.1.149",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.6.*",
                  "status": "unaffected",
                  "version": "6.6.103",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.12.*",
                  "status": "unaffected",
                  "version": "6.12.44",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.16.*",
                  "status": "unaffected",
                  "version": "6.16.4",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "6.17",
                  "versionType": "original_commit_for_fix"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.1.149",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.6.103",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.12.44",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.16.4",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.17",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntls: fix handling of zero-length records on the rx_list\n\nEach recvmsg() call must process either\n - only contiguous DATA records (any number of them)\n - one non-DATA record\n\nIf the next record has different type than what has already been\nprocessed we break out of the main processing loop. If the record\nhas already been decrypted (which may be the case for TLS 1.3 where\nwe don\u0027t know type until decryption) we queue the pending record\nto the rx_list. Next recvmsg() will pick it up from there.\n\nQueuing the skb to rx_list after zero-copy decrypt is not possible,\nsince in that case we decrypted directly to the user space buffer,\nand we don\u0027t have an skb to queue (darg.skb points to the ciphertext\nskb for access to metadata like length).\n\nOnly data records are allowed zero-copy, and we break the processing\nloop after each non-data record. So we should never zero-copy and\nthen find out that the record type has changed. The corner case\nwe missed is when the initial record comes from rx_list, and it\u0027s\nzero length."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:N - The bug is triggered entirely by the sequence and content of TLS records arriving from the remote peer on a kTLS-enabled TCP socket (net/tls RX path); no local access is needed. Any kTLS RX consumer \u2014 OpenSSL-with-kTLS servers/clients, NFS-over-TLS, SMB/RPC-over-TLS via net/handshake \u2014 is remotely reachable over the network.\nAC:L - The attacker sends three back-to-back records ([DATA][zero-length non-DATA][DATA]) and the corruption occurs deterministically on the victim\u0027s ordinary recvmsg() loop, with no race to win and no memory-layout dependency; the kernel selftest added with the fix reproduces it in one shot. TLS 1.2 is zero-copy-capable by default (zc_capable = rx_no_pad || version != TLS_1_3_VERSION), so no unusual kernel config or sockopt is required.\nPR:N - The attacker is the remote TLS peer, which holds no privileges on the target system \u2014 an anonymous client completing a server-authenticated TLS handshake with a kTLS server, or a malicious server that a kTLS client connects to, suffices. This matches the repo\u0027s PR:N scoring of the comparable remote-peer net/tls bug CVE-2025-39946.\nUI:N - The victim application only has to run its normal recvmsg() loop on an already-established kTLS socket; no click, mount, file open, or any other victim action is required. The attacker drives the entire trigger from the wire.\nS:U - The corruption is confined to kernel skb/slab state within the same security authority; there is no VM, IOMMU, or sandbox boundary crossed. Standard in-kernel memory corruption is Scope:Unchanged.\nC:H - The strparser anchor is queued on rx_list after tcp_read_done() already released its backing TCP skbs, so the next recvmsg() copies freed kernel heap memory straight into the userspace buffer via skb_copy_datagram_msg(). This is a directly usable, repeatable kernel-memory disclosure primitive, not a bounded pointer leak.\nI:H - The live strp-\u003eanchor is consume_skb()\u0027d by process_rx_list() while the strparser still uses it, after which incoming attacker-controlled TCP data is written into the freed sk_buff/skb_shared_info (skb_fill_page_desc, tls_strp_load_anchor_with_queue), and socket teardown double-frees the anchor and its frag_list skbs. This yields attacker-controlled write-after-free and freelist corruption suitable for control-flow hijack.\nA:H - The use-after-free and double-free of the anchor and of already-released TCP receive-queue skbs reliably corrupt slab state, producing oopses/panics and list corruption. Any remote peer can repeat this on every connection, giving a trivial remote kernel-crash DoS."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-05T12:04:31.384Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/2902c3ebcca52ca845c03182000e8d71d3a5196f"
            },
            {
              "url": "https://git.kernel.org/stable/c/c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677"
            },
            {
              "url": "https://git.kernel.org/stable/c/3439c15ae91a517cf3c650ea15a8987699416ad9"
            },
            {
              "url": "https://git.kernel.org/stable/c/29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e"
            },
            {
              "url": "https://git.kernel.org/stable/c/62708b9452f8eb77513115b17c4f8d1a22ebf843"
            }
          ],
          "title": "tls: fix handling of zero-length records on the rx_list",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2025-39682",
        "datePublished": "2025-09-05T17:20:48.657Z",
        "dateReserved": "2025-04-16T07:20:57.113Z",
        "dateUpdated": "2026-09-19T03:56:24.457Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.