{"id":"CVE-2026-31495","title":"netfilter: ctnetlink: use netlink policy range checks","summary":"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 ne…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 435b576cd2faa75154777868f8cbb73bf71644d3","Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 2ef71307c86a9f866d6e28f1a0c06e2e9d794474","Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 4f7d25f3f0786402ba48ff7d13b6241d77d975f5","Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < fcec5ce2d73a41668b24e3f18c803541602a59f6","Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 675c913b940488a84effdeeac5a1cfb657b59804","Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < c6cb41eaae875501eaaa487b8db6539feb092292","Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 45c33e79ae705b7af97e3117672b6cd258dd0b1b","Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 8f15b5071b4548b0aafc03b366eb45c9c6566704","Linux 2.6.22"],"published":"2026-04-22","updated":"2026-09-08","sourceUpdated":"2026-09-08T08:47:26.322Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-31495","references":[{"url":"https://git.kernel.org/stable/c/435b576cd2faa75154777868f8cbb73bf71644d3"},{"url":"https://git.kernel.org/stable/c/2ef71307c86a9f866d6e28f1a0c06e2e9d794474"},{"url":"https://git.kernel.org/stable/c/4f7d25f3f0786402ba48ff7d13b6241d77d975f5"},{"url":"https://git.kernel.org/stable/c/fcec5ce2d73a41668b24e3f18c803541602a59f6"},{"url":"https://git.kernel.org/stable/c/675c913b940488a84effdeeac5a1cfb657b59804"},{"url":"https://git.kernel.org/stable/c/c6cb41eaae875501eaaa487b8db6539feb092292"},{"url":"https://git.kernel.org/stable/c/45c33e79ae705b7af97e3117672b6cd258dd0b1b"},{"url":"https://git.kernel.org/stable/c/8f15b5071b4548b0aafc03b366eb45c9c6566704"}],"tags":["cve.org"],"epss":0.00129,"epssPercentile":0.02884,"ingestedAt":"2026-09-08T15:33:26.990Z","slug":"CVE-2026-31495","body":"## Overview\n\nIn 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 > TCP_CONNTRACK_SYN_SENT2 at\n  policy level, removing the manual >= TCP_CONNTRACK_MAX check.\n- CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values > 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.\n\n## Affected\n\n- `Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 435b576cd2faa75154777868f8cbb73bf71644d3`\n- `Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 2ef71307c86a9f866d6e28f1a0c06e2e9d794474`\n- `Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 4f7d25f3f0786402ba48ff7d13b6241d77d975f5`\n- `Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < fcec5ce2d73a41668b24e3f18c803541602a59f6`\n- `Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 675c913b940488a84effdeeac5a1cfb657b59804`\n- `Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < c6cb41eaae875501eaaa487b8db6539feb092292`\n- `Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 45c33e79ae705b7af97e3117672b6cd258dd0b1b`\n- `Linux >= c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 < 8f15b5071b4548b0aafc03b366eb45c9c6566704`\n- `Linux 2.6.22`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}