CVE-2026-74406 (GCVE-0-2026-74406)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:59 – Updated: 2026-08-17 05:46
VLAI
Title
vxlan: Fix potential null-ptr-deref in vxlan_gro_prepare_receive().
Summary
In the Linux kernel, the following vulnerability has been resolved: vxlan: Fix potential null-ptr-deref in vxlan_gro_prepare_receive(). udp_tunnel_sock_release() could set sk->sk_user_data to NULL while vxlan_gro_prepare_receive() is running. Let's check if rcu_dereference_sk_user_data() is NULL after skb_gro_remcsum_init().
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 5602c48cf87562c2f95b831d690631935e834295 , < 9c58c729d32e7cea5772cc44929c6cd61e5a31cd (git)
Affected: 5602c48cf87562c2f95b831d690631935e834295 , < f79c80f173fda9545b220c1f094b65fc06c252d0 (git)
Affected: 5602c48cf87562c2f95b831d690631935e834295 , < 08f40c0d23c67c3aa4224c3311e134999c721fb4 (git)
Affected: 5602c48cf87562c2f95b831d690631935e834295 , < 4a8cde6f7281ea2c4c290f9ad9923b3631defceb (git)
Affected: 5602c48cf87562c2f95b831d690631935e834295 , < ef44dac2a37f86eeae6b88ed10a6d60b35387dfd (git)
Affected: 5602c48cf87562c2f95b831d690631935e834295 , < 30a45c0bffdd62350261e2f2689fdba426a33578 (git)
guessed Create a notification for this product.
Linux Linux Affected: 4.7
Unaffected: 0 , < 4.7 (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/vxlan/vxlan_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9c58c729d32e7cea5772cc44929c6cd61e5a31cd",
              "status": "affected",
              "version": "5602c48cf87562c2f95b831d690631935e834295",
              "versionType": "git"
            },
            {
              "lessThan": "f79c80f173fda9545b220c1f094b65fc06c252d0",
              "status": "affected",
              "version": "5602c48cf87562c2f95b831d690631935e834295",
              "versionType": "git"
            },
            {
              "lessThan": "08f40c0d23c67c3aa4224c3311e134999c721fb4",
              "status": "affected",
              "version": "5602c48cf87562c2f95b831d690631935e834295",
              "versionType": "git"
            },
            {
              "lessThan": "4a8cde6f7281ea2c4c290f9ad9923b3631defceb",
              "status": "affected",
              "version": "5602c48cf87562c2f95b831d690631935e834295",
              "versionType": "git"
            },
            {
              "lessThan": "ef44dac2a37f86eeae6b88ed10a6d60b35387dfd",
              "status": "affected",
              "version": "5602c48cf87562c2f95b831d690631935e834295",
              "versionType": "git"
            },
            {
              "lessThan": "30a45c0bffdd62350261e2f2689fdba426a33578",
              "status": "affected",
              "version": "5602c48cf87562c2f95b831d690631935e834295",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/vxlan/vxlan_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.7"
            },
            {
              "lessThan": "4.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "4.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: Fix potential null-ptr-deref in vxlan_gro_prepare_receive().\n\nudp_tunnel_sock_release() could set sk-\u003esk_user_data to NULL\nwhile vxlan_gro_prepare_receive() is running.\n\nLet\u0027s check if rcu_dereference_sk_user_data() is NULL after\nskb_gro_remcsum_init()."
        }
      ],
      "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 in vxlan_gro_prepare_receive() on the UDP GRO receive path; remote VXLAN/UDP packets reach it via inet_gro_receive\u2192udp4_gro_receive\u2192udp_tunnel_gro_rcv\u2192vxlan_gro_receive during NAPI processing on internet/cloud overlay endpoints.\nAC:L - An attacker can reliably trigger the race by flooding VXLAN GRO packets while concurrently tearing down the VXLAN device (e.g., via CAP_NET_ADMIN in a user namespace); repeated attempts during orchestrated interface churn also make the timing window attacker-driven rather than purely environmental.\nPR:N - Exploitation requires only the ability to send crafted VXLAN UDP traffic to a listening tunnel port; no target credentials or local account are needed, and concurrent teardown can occur from normal administrative or automation activity rather than attacker-held privileges.\nUI:N - No victim interaction is required beyond the host already running a VXLAN interface; the attacker triggers the fault purely by sending network packets timed against interface teardown.\nS:U - Impact is a kernel fault in networking softirq context on the same host; it does not cross VM, container, or IOMMU security boundaries into another authority.\nC:H - The race can leave a stale vxlan_sock pointer after udp_tunnel_sock_release() frees sk_user_data; dereferencing vs-\u003eflags is a use-after-free read that can expose kernel heap contents and is treated as arbitrary read potential under conservative scoring.\nI:H - Use-after-free on the vxlan_sock object during GRO teardown can corrupt heap metadata or adjacent objects and be leveraged for control-flow hijacking, not merely a benign NULL check failure.\nA:H - A successful trigger causes a kernel NULL pointer dereference/oops in NAPI/softirq context (documented crash at vxlan_gro_prepare_receive), typically crashing or hanging the host and denying all services."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:46:49.365Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9c58c729d32e7cea5772cc44929c6cd61e5a31cd"
        },
        {
          "url": "https://git.kernel.org/stable/c/f79c80f173fda9545b220c1f094b65fc06c252d0"
        },
        {
          "url": "https://git.kernel.org/stable/c/08f40c0d23c67c3aa4224c3311e134999c721fb4"
        },
        {
          "url": "https://git.kernel.org/stable/c/4a8cde6f7281ea2c4c290f9ad9923b3631defceb"
        },
        {
          "url": "https://git.kernel.org/stable/c/ef44dac2a37f86eeae6b88ed10a6d60b35387dfd"
        },
        {
          "url": "https://git.kernel.org/stable/c/30a45c0bffdd62350261e2f2689fdba426a33578"
        }
      ],
      "title": "vxlan: Fix potential null-ptr-deref in vxlan_gro_prepare_receive().",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74406",
    "datePublished": "2026-08-15T05:59:15.385Z",
    "dateReserved": "2026-08-15T05:44:03.892Z",
    "dateUpdated": "2026-08-17T05:46:49.365Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74406",
      "date": "2026-09-21",
      "epss": "0.00491",
      "percentile": "0.4115"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "drivers/net/vxlan/vxlan_core.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "9c58c729d32e7cea5772cc44929c6cd61e5a31cd",
                    "status": "affected",
                    "version": "5602c48cf87562c2f95b831d690631935e834295",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "f79c80f173fda9545b220c1f094b65fc06c252d0",
                    "status": "affected",
                    "version": "5602c48cf87562c2f95b831d690631935e834295",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "08f40c0d23c67c3aa4224c3311e134999c721fb4",
                    "status": "affected",
                    "version": "5602c48cf87562c2f95b831d690631935e834295",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "4a8cde6f7281ea2c4c290f9ad9923b3631defceb",
                    "status": "affected",
                    "version": "5602c48cf87562c2f95b831d690631935e834295",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "ef44dac2a37f86eeae6b88ed10a6d60b35387dfd",
                    "status": "affected",
                    "version": "5602c48cf87562c2f95b831d690631935e834295",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "30a45c0bffdd62350261e2f2689fdba426a33578",
                    "status": "affected",
                    "version": "5602c48cf87562c2f95b831d690631935e834295",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "drivers/net/vxlan/vxlan_core.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "4.7"
                  },
                  {
                    "lessThan": "4.7",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.178",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.145",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.97",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.40",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.1.*",
                    "status": "unaffected",
                    "version": "7.1.5",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.2",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: Fix potential null-ptr-deref in vxlan_gro_prepare_receive().\n\nudp_tunnel_sock_release() could set sk-\u003esk_user_data to NULL\nwhile vxlan_gro_prepare_receive() is running.\n\nLet\u0027s check if rcu_dereference_sk_user_data() is NULL after\nskb_gro_remcsum_init()."
          }
        ],
        "id": "CVE-2026-74406",
        "lastModified": "2026-08-17T06:19:35.850",
        "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"
            }
          ]
        },
        "published": "2026-08-15T06:22:42.633",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/08f40c0d23c67c3aa4224c3311e134999c721fb4"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/30a45c0bffdd62350261e2f2689fdba426a33578"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/4a8cde6f7281ea2c4c290f9ad9923b3631defceb"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/9c58c729d32e7cea5772cc44929c6cd61e5a31cd"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/ef44dac2a37f86eeae6b88ed10a6d60b35387dfd"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/f79c80f173fda9545b220c1f094b65fc06c252d0"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T10:28:08+00:00",
      "cve": "CVE-2026-74406",
      "id": "CVE-2026-74406",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: vxlan: Fix potential null-ptr-deref in vxlan_gro_prepare_receive()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74406.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-15T01:21:26Z",
      "cve": "CVE-2026-74406",
      "id": "CVE-2026-74406",
      "initial_release_date": "2026-08-25T01:21:18Z",
      "product_status:first_fixed": "92",
      "product_status:known_affected": "356",
      "product_status:known_not_affected": "6",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74406",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74406.json",
      "version": "4"
    }
  }
}



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.