CVE-2026-31495 (GCVE-0-2026-31495)

Vulnerability from cvelistv5 – Published: 2026-04-22 13:54 – Updated: 2026-04-22 13:54
VLAI?
Title
netfilter: ctnetlink: use netlink policy range checks
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: use netlink policy range checks Replace manual range and mask validations with netlink policy annotations in ctnetlink code paths, so that the netlink core rejects invalid values early and can generate extack errors. - CTA_PROTOINFO_TCP_STATE: reject values > TCP_CONNTRACK_SYN_SENT2 at policy level, removing the manual >= TCP_CONNTRACK_MAX check. - CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values > TCP_MAX_WSCALE (14). The normal TCP option parsing path already clamps to this value, but the ctnetlink path accepted 0-255, causing undefined behavior when used as a u32 shift count. - CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with CTA_FILTER_F_ALL, removing the manual mask checks. - CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding a new mask define grouping all valid expect flags. Extracted from a broader nf-next patch by Florian Westphal, scoped to ctnetlink for the fixes tree.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 , < 435b576cd2faa75154777868f8cbb73bf71644d3 (git)
Affected: c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 , < 2ef71307c86a9f866d6e28f1a0c06e2e9d794474 (git)
Affected: c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 , < 4f7d25f3f0786402ba48ff7d13b6241d77d975f5 (git)
Affected: c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 , < fcec5ce2d73a41668b24e3f18c803541602a59f6 (git)
Affected: c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 , < 675c913b940488a84effdeeac5a1cfb657b59804 (git)
Affected: c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 , < c6cb41eaae875501eaaa487b8db6539feb092292 (git)
Affected: c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 , < 45c33e79ae705b7af97e3117672b6cd258dd0b1b (git)
Affected: c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 , < 8f15b5071b4548b0aafc03b366eb45c9c6566704 (git)
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    Linux Linux Affected: 2.6.22
Unaffected: 0 , < 2.6.22 (semver)
Unaffected: 5.10.253 , ≤ 5.10.* (semver)
Unaffected: 5.15.203 , ≤ 5.15.* (semver)
Unaffected: 6.1.168 , ≤ 6.1.* (semver)
Unaffected: 6.6.131 , ≤ 6.6.* (semver)
Unaffected: 6.12.80 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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          "product": "Linux",
          "programFiles": [
            "include/uapi/linux/netfilter/nf_conntrack_common.h",
            "net/netfilter/nf_conntrack_netlink.c",
            "net/netfilter/nf_conntrack_proto_tcp.c"
          ],
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          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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            "net/netfilter/nf_conntrack_netlink.c",
            "net/netfilter/nf_conntrack_proto_tcp.c"
          ],
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          "vendor": "Linux",
          "versions": [
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            },
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              "status": "unaffected",
              "version": "5.15.203",
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            },
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              "status": "unaffected",
              "version": "6.18.21",
              "versionType": "semver"
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              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: use netlink policy range checks\n\nReplace manual range and mask validations with netlink policy\nannotations in ctnetlink code paths, so that the netlink core rejects\ninvalid values early and can generate extack errors.\n\n- CTA_PROTOINFO_TCP_STATE: reject values \u003e TCP_CONNTRACK_SYN_SENT2 at\n  policy level, removing the manual \u003e= TCP_CONNTRACK_MAX check.\n- CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values \u003e TCP_MAX_WSCALE\n  (14). The normal TCP option parsing path already clamps to this value,\n  but the ctnetlink path accepted 0-255, causing undefined behavior when\n  used as a u32 shift count.\n- CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with\n  CTA_FILTER_F_ALL, removing the manual mask checks.\n- CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding\n  a new mask define grouping all valid expect flags.\n\nExtracted from a broader nf-next patch by Florian Westphal, scoped to\nctnetlink for the fixes tree."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-22T13:54:17.591Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/435b576cd2faa75154777868f8cbb73bf71644d3"
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        {
          "url": "https://git.kernel.org/stable/c/2ef71307c86a9f866d6e28f1a0c06e2e9d794474"
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          "url": "https://git.kernel.org/stable/c/675c913b940488a84effdeeac5a1cfb657b59804"
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          "url": "https://git.kernel.org/stable/c/45c33e79ae705b7af97e3117672b6cd258dd0b1b"
        },
        {
          "url": "https://git.kernel.org/stable/c/8f15b5071b4548b0aafc03b366eb45c9c6566704"
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      "title": "netfilter: ctnetlink: use netlink policy range checks",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31495",
    "datePublished": "2026-04-22T13:54:17.591Z",
    "dateReserved": "2026-03-09T15:48:24.102Z",
    "dateUpdated": "2026-04-22T13:54:17.591Z",
    "state": "PUBLISHED"
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  }
}


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  • 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.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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