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

CVE-2026-80844 (GCVE-0-2026-80844)

Vulnerability from cvelistv5 – Published: 2026-09-04 15:54 – Updated: 2026-09-04 15:54
VLAI
Title
xfrm: ah6: validate routing header segments_left
Summary
In the Linux kernel, the following vulnerability has been resolved: xfrm: ah6: validate routing header segments_left AH6 rearranges routing-header addresses before computing or verifying the ICV. ipv6_rearrange_rthdr() assumes that segments_left is not larger than the number of addresses described by the routing header's hdrlen field. That assumption does not hold for raw IPv6 HDRINCL packets. A packet with hdrlen equal to 2 describes one address, but can carry an arbitrary segments_left value. With segments_left equal to 255, the function moves its address pointer 4,064 bytes backwards and passes a 4,064-byte length to memmove(), resulting in an out-of-bounds access. Validate the invariant locally before modifying the routing header or performing any address-pointer arithmetic, and propagate malformed-header errors to the existing AH6 input and output error paths.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 2dc650956e4e163b879b3fb1027f9557abc5c985 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 48b0e36cf54358276ee7aa897034c973097d2bc9 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 1b7e066eabcc7d6d8f476c34739b45932f2f4c31 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < f00df8500e5a36ba70d336fd34bd2152ea074e5f (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 1516e31ac458a738be485620579d8f7fb2700fcb (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 6733ae71268a27d598cfb3f3339a3c950b9b656d (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 0bf11081ad3753938a2b48723ce6298dbac743a1 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 46640c814f25f096b0b0045ca50e1b7030cd8a30 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 7bad4bda74dc4713f398d3b7624ff05478e3a568 (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.12
Unaffected: 0 , < 2.6.12 (semver)
Unaffected: 5.10.269 , ≤ 5.10.* (semver)
Unaffected: 5.15.220 , ≤ 5.15.* (semver)
Unaffected: 6.1.187 , ≤ 6.1.* (semver)
Unaffected: 6.6.156 , ≤ 6.6.* (semver)
Unaffected: 6.12.108 , ≤ 6.12.* (semver)
Unaffected: 6.18.49 , ≤ 6.18.* (semver)
Unaffected: 7.1.13 , ≤ 7.1.* (semver)
Unaffected: 7.2.3 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (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": [
            "net/ipv6/ah6.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2dc650956e4e163b879b3fb1027f9557abc5c985",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "48b0e36cf54358276ee7aa897034c973097d2bc9",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "1b7e066eabcc7d6d8f476c34739b45932f2f4c31",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "f00df8500e5a36ba70d336fd34bd2152ea074e5f",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "1516e31ac458a738be485620579d8f7fb2700fcb",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "6733ae71268a27d598cfb3f3339a3c950b9b656d",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "0bf11081ad3753938a2b48723ce6298dbac743a1",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "46640c814f25f096b0b0045ca50e1b7030cd8a30",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "7bad4bda74dc4713f398d3b7624ff05478e3a568",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ah6.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "lessThan": "2.6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.269",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.220",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.187",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.156",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.108",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.49",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.269",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.220",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.187",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.156",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.108",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.49",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.13",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.3",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: ah6: validate routing header segments_left\n\nAH6 rearranges routing-header addresses before computing or verifying the\nICV. ipv6_rearrange_rthdr() assumes that segments_left is not larger than\nthe number of addresses described by the routing header\u0027s hdrlen field.\n\nThat assumption does not hold for raw IPv6 HDRINCL packets. A packet with\nhdrlen equal to 2 describes one address, but can carry an arbitrary\nsegments_left value. With segments_left equal to 255, the function moves\nits address pointer 4,064 bytes backwards and passes a 4,064-byte length to\nmemmove(), resulting in an out-of-bounds access.\n\nValidate the invariant locally before modifying the routing header or\nperforming any address-pointer arithmetic, and propagate malformed-header\nerrors to the existing AH6 input and output error paths."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-04T15:54:54.295Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2dc650956e4e163b879b3fb1027f9557abc5c985"
        },
        {
          "url": "https://git.kernel.org/stable/c/48b0e36cf54358276ee7aa897034c973097d2bc9"
        },
        {
          "url": "https://git.kernel.org/stable/c/1b7e066eabcc7d6d8f476c34739b45932f2f4c31"
        },
        {
          "url": "https://git.kernel.org/stable/c/f00df8500e5a36ba70d336fd34bd2152ea074e5f"
        },
        {
          "url": "https://git.kernel.org/stable/c/1516e31ac458a738be485620579d8f7fb2700fcb"
        },
        {
          "url": "https://git.kernel.org/stable/c/6733ae71268a27d598cfb3f3339a3c950b9b656d"
        },
        {
          "url": "https://git.kernel.org/stable/c/0bf11081ad3753938a2b48723ce6298dbac743a1"
        },
        {
          "url": "https://git.kernel.org/stable/c/46640c814f25f096b0b0045ca50e1b7030cd8a30"
        },
        {
          "url": "https://git.kernel.org/stable/c/7bad4bda74dc4713f398d3b7624ff05478e3a568"
        }
      ],
      "title": "xfrm: ah6: validate routing header segments_left",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80844",
    "datePublished": "2026-09-04T15:54:54.295Z",
    "dateReserved": "2026-08-26T14:34:25.796Z",
    "dateUpdated": "2026-09-04T15:54:54.295Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-80844",
      "date": "2026-09-18",
      "epss": "0.00195",
      "percentile": "0.09543"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-07T02:03:28.000Z",
      "cve": "CVE-2026-80844",
      "id": "msrc_CVE-2026-80844",
      "initial_release_date": "2026-09-06T04:36:08.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "xfrm: ah6: validate routing header segments_left",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-80844.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/ipv6/ah6.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "2dc650956e4e163b879b3fb1027f9557abc5c985",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "48b0e36cf54358276ee7aa897034c973097d2bc9",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "1b7e066eabcc7d6d8f476c34739b45932f2f4c31",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "f00df8500e5a36ba70d336fd34bd2152ea074e5f",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "1516e31ac458a738be485620579d8f7fb2700fcb",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "6733ae71268a27d598cfb3f3339a3c950b9b656d",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "0bf11081ad3753938a2b48723ce6298dbac743a1",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "46640c814f25f096b0b0045ca50e1b7030cd8a30",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "7bad4bda74dc4713f398d3b7624ff05478e3a568",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/ipv6/ah6.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "2.6.12"
                  },
                  {
                    "lessThan": "2.6.12",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.10.*",
                    "status": "unaffected",
                    "version": "5.10.269",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.15.*",
                    "status": "unaffected",
                    "version": "5.15.220",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.187",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.156",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.108",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.49",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.1.*",
                    "status": "unaffected",
                    "version": "7.1.13",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.2.*",
                    "status": "unaffected",
                    "version": "7.2.3",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.3-rc1",
                    "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\nxfrm: ah6: validate routing header segments_left\n\nAH6 rearranges routing-header addresses before computing or verifying the\nICV. ipv6_rearrange_rthdr() assumes that segments_left is not larger than\nthe number of addresses described by the routing header\u0027s hdrlen field.\n\nThat assumption does not hold for raw IPv6 HDRINCL packets. A packet with\nhdrlen equal to 2 describes one address, but can carry an arbitrary\nsegments_left value. With segments_left equal to 255, the function moves\nits address pointer 4,064 bytes backwards and passes a 4,064-byte length to\nmemmove(), resulting in an out-of-bounds access.\n\nValidate the invariant locally before modifying the routing header or\nperforming any address-pointer arithmetic, and propagate malformed-header\nerrors to the existing AH6 input and output error paths."
          }
        ],
        "id": "CVE-2026-80844",
        "lastModified": "2026-09-04T16:18:13.023",
        "metrics": {},
        "published": "2026-09-04T16:18:13.023",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/0bf11081ad3753938a2b48723ce6298dbac743a1"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/1516e31ac458a738be485620579d8f7fb2700fcb"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/1b7e066eabcc7d6d8f476c34739b45932f2f4c31"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/2dc650956e4e163b879b3fb1027f9557abc5c985"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/46640c814f25f096b0b0045ca50e1b7030cd8a30"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/48b0e36cf54358276ee7aa897034c973097d2bc9"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/6733ae71268a27d598cfb3f3339a3c950b9b656d"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/7bad4bda74dc4713f398d3b7624ff05478e3a568"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/f00df8500e5a36ba70d336fd34bd2152ea074e5f"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-17T16:57:10Z",
      "cve": "CVE-2026-80844",
      "id": "CVE-2026-80844",
      "initial_release_date": "2026-09-05T00:26:22Z",
      "product_status:known_affected": "353",
      "product_status:recommended": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-80844",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-80844.json",
      "version": "5"
    }
  }
}



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.