{"id":"CVE-2026-31495","title":"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…","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":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 2.6.22.1, < 5.10.253","linux_kernel >= 5.11, < 5.15.203","linux_kernel >= 5.16, < 6.1.168","linux_kernel >= 6.2, < 6.6.131","linux_kernel >= 6.7, < 6.12.80","linux_kernel >= 6.13, < 6.18.21","linux_kernel >= 6.19, < 6.19.11","linux_kernel = 2.6.22","linux_kernel = 7.0"],"patched":["linux_kernel 6.19.11"],"published":"2026-04-22","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:19:08.387","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-31495","references":[{"url":"https://git.kernel.org/stable/c/2ef71307c86a9f866d6e28f1a0c06e2e9d794474","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/435b576cd2faa75154777868f8cbb73bf71644d3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/45c33e79ae705b7af97e3117672b6cd258dd0b1b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4f7d25f3f0786402ba48ff7d13b6241d77d975f5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/675c913b940488a84effdeeac5a1cfb657b59804","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8f15b5071b4548b0aafc03b366eb45c9c6566704","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c6cb41eaae875501eaaa487b8db6539feb092292","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fcec5ce2d73a41668b24e3f18c803541602a59f6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00129,"epssPercentile":0.02499,"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_kernel >= 2.6.22.1, < 5.10.253`\n- `linux_kernel >= 5.11, < 5.15.203`\n- `linux_kernel >= 5.16, < 6.1.168`\n- `linux_kernel >= 6.2, < 6.6.131`\n- `linux_kernel >= 6.7, < 6.12.80`\n- `linux_kernel >= 6.13, < 6.18.21`\n- `linux_kernel >= 6.19, < 6.19.11`\n- `linux_kernel = 2.6.22`\n- `linux_kernel = 7.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.19.11`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":221717,"id":"CVE-2026-31495","ts":1792035335495,"field":"cvss","old":null,"new":"5.5"},{"seq":221716,"id":"CVE-2026-31495","ts":1792035335495,"field":"severity","old":"none","new":"medium"}]}