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

Vulnerability from cvelistv5 – Published: 2025-09-05 17:20 – Updated: 2026-08-05 12:04
VLAI
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: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < 2902c3ebcca52ca845c03182000e8d71d3a5196f (git)
Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677 (git)
Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < 3439c15ae91a517cf3c650ea15a8987699416ad9 (git)
Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < 29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e (git)
Affected: 84c61fe1a75b4255df1e1e7c054c9e6d048da417 , < 62708b9452f8eb77513115b17c4f8d1a22ebf843 (git)
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)
Create a notification for this product.
Siemens SIMATIC CN 4100 Affected: 0 , < V5.0 (custom)
Create a notification for this product.
Show details on NVD website
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-30T09:03:24+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_affected": "22",
      "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"
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      "current_release_date": "2026-07-25T00:41:46Z",
      "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": "268",
      "product_status:recommended": "609",
      "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": "55"
    },
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The corner case\\nwe missed is when the initial record comes from rx_list, and it\u0027s\\nzero length.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.149\", \"versionStartIncluding\": \"6.0\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.103\", \"versionStartIncluding\": \"6.0\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.44\", \"versionStartIncluding\": \"6.0\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.16.4\", \"versionStartIncluding\": \"6.0\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.17\", \"versionStartIncluding\": \"6.0\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T12:04:31.384Z\"}}}",
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      "dataType": "CVE_RECORD",
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    }
  }
}



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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.