CVE-2026-98568 (GCVE-0-2026-98568)
Vulnerability from cvelistv5
Published
2026-10-18 15:18
Modified
2026-10-30 12:38
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: vxlan: use one headroom snapshot for neighbour replies vxlan_na_create() samples LL_RESERVED_SPACE() to size the reply skb and then samples it again to reserve headroom. A concurrent vxlan_changelink() can update needed_headroom between the two reads, creating a TOCTOU race. The second value can exceed the allocation and make the Ethernet header write out of bounds. The race is reproducible on the unpatched kernel. It occurred when vxlan_na_create() generated a neighbour reply while vxlan_changelink() changed the link headroom. KASAN caught a four-byte write two bytes beyond a 704-byte skbuff_small_head allocation. Snapshot the headroom once and use that value for both allocation and reservation.
References
Impacted products
Vendor Product Version
Linux Linux Version: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa
Version: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa
Version: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa
Version: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa
Version: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa
Version: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa
Version: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa
Version: 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa
Version: d8be18c52dbc94989f6d74637b731af39cd3d902
Version: 3927dace523706cc00f808520eaf2125dd7c07b5
Version: 3.12.18   ≤
Version: 3.13.10   ≤
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": "e3e24f4c434c56952412f875b834aa9daaa4fb15",
              "status": "affected",
              "version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
              "versionType": "git"
            },
            {
              "lessThan": "9ed5a548b42d46e6968a46b67ca8a8e49b12a5a1",
              "status": "affected",
              "version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
              "versionType": "git"
            },
            {
              "lessThan": "fcaf456092dc86fd5b0b523ac27ec0d114066931",
              "status": "affected",
              "version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
              "versionType": "git"
            },
            {
              "lessThan": "45a67662bf8ce3aa5643accf98d328dfbb47eaf6",
              "status": "affected",
              "version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
              "versionType": "git"
            },
            {
              "lessThan": "315d42ca39f69846662961c25dcf2bb07c350d14",
              "status": "affected",
              "version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
              "versionType": "git"
            },
            {
              "lessThan": "a3c5eb6e382dd426a5e7eb08608897ed57167ff7",
              "status": "affected",
              "version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
              "versionType": "git"
            },
            {
              "lessThan": "ff022fd9d0f0282c575e11778b96bd1b637503eb",
              "status": "affected",
              "version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
              "versionType": "git"
            },
            {
              "lessThan": "481506a756dcd828ef42391cb08f38d8d96d38fc",
              "status": "affected",
              "version": "4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d8be18c52dbc94989f6d74637b731af39cd3d902",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3927dace523706cc00f808520eaf2125dd7c07b5",
              "versionType": "git"
            },
            {
              "lessThan": "3.13",
              "status": "affected",
              "version": "3.12.18",
              "versionType": "semver"
            },
            {
              "lessThan": "3.14",
              "status": "affected",
              "version": "3.13.10",
              "versionType": "semver"
            }
          ]
        },
        {
          "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": "3.14"
            },
            {
              "lessThan": "3.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.273",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.55",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.273",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.224",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.191",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.158",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.55",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.9",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "3.12.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "3.13.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: use one headroom snapshot for neighbour replies\n\nvxlan_na_create() samples LL_RESERVED_SPACE() to size the reply skb and then\nsamples it again to reserve headroom. A concurrent vxlan_changelink() can\nupdate needed_headroom between the two reads, creating a TOCTOU race. The\nsecond value can exceed the allocation and make the Ethernet header write out\nof bounds.\n\nThe race is reproducible on the unpatched kernel. It occurred when\nvxlan_na_create() generated a neighbour reply while vxlan_changelink() changed\nthe link headroom. KASAN caught a four-byte write two bytes beyond a 704-byte\nskbuff_small_head allocation.\n\nSnapshot the headroom once and use that value for both allocation and\nreservation."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:38:26.027Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e3e24f4c434c56952412f875b834aa9daaa4fb15"
        },
        {
          "url": "https://git.kernel.org/stable/c/9ed5a548b42d46e6968a46b67ca8a8e49b12a5a1"
        },
        {
          "url": "https://git.kernel.org/stable/c/fcaf456092dc86fd5b0b523ac27ec0d114066931"
        },
        {
          "url": "https://git.kernel.org/stable/c/45a67662bf8ce3aa5643accf98d328dfbb47eaf6"
        },
        {
          "url": "https://git.kernel.org/stable/c/315d42ca39f69846662961c25dcf2bb07c350d14"
        },
        {
          "url": "https://git.kernel.org/stable/c/a3c5eb6e382dd426a5e7eb08608897ed57167ff7"
        },
        {
          "url": "https://git.kernel.org/stable/c/ff022fd9d0f0282c575e11778b96bd1b637503eb"
        },
        {
          "url": "https://git.kernel.org/stable/c/481506a756dcd828ef42391cb08f38d8d96d38fc"
        }
      ],
      "title": "vxlan: use one headroom snapshot for neighbour replies",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98568",
    "datePublished": "2026-10-18T15:18:34.562Z",
    "dateReserved": "2026-09-25T10:25:14.357Z",
    "dateUpdated": "2026-10-30T12:38:26.027Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.