{"id":"CVE-2026-72418","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conncount: prevent connlimit drops for early confirmed ct\n\nCommit 69894e5b4c5e (\"netfilter: nft_connlimit: update the count if add\nwas skipped\") introduce…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conncount: prevent connlimit drops for early confirmed ct\n\nCommit 69894e5b4c5e (\"netfilter: nft_connlimit: update the count if add\nwas skipped\") introduce…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-367"],"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","affected":["enterprise_linux 10"],"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T19:17:29.033","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-72418","references":[{"url":"https://git.kernel.org/stable/c/000ac6830b56499d6b65fd91486ce6689eb02be4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/329f2626ee5cb8fafdf6b58b624311529c57cb45","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3793d24de224943e0a6016bbeffb6f5c4cea2e3d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/abef7f817217fcb62c11821d6b895063eadb2828","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/be52572c6d55f677ba76869d3c63805c0d4891a3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c8b6f36f766991e3ebebec6596daee4b04dcbc49","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cbe2d14a7c5b1fc71821fbfee5c4963917411e92","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ebfe8249ba79e4ff0f1e3aad8787b992ef27f026","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72418.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-72418"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2516428"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72418"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72418"},{"url":"https://lore.kernel.org/linux-cve-announce/2026081525-CVE-2026-72418-185c@gregkh/T"}],"tags":["nvd","csaf","vex","red-hat","cve.org","score-dispute"],"epss":0.00716,"epssPercentile":0.53585,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-16T18:49:23.434729Z"},"scores":{"nvd":7.5,"vendor":5.5,"cna":7.5},"ingestedAt":"2026-10-16T19:46:24.398Z","slug":"CVE-2026-72418","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conncount: prevent connlimit drops for early confirmed ct\n\nCommit 69894e5b4c5e (\"netfilter: nft_connlimit: update the count if add\nwas skipped\") introduced a regression where packets for valid\nconnections are dropped when using connlimit for soft-limiting\nscenarios.\n\nThe issue occurs when a new connection reuses a socket currently in\nthe TIME_WAIT state. In this scenario, the connection tracking entry\nis evaluated as already confirmed. Previously, __nf_conncount_add()\nassumed that if a connection was confirmed and did not originate from\nthe loopback interface, it should skip the addition and return -EEXIST.\n\nSkipping the addition triggers a garbage collection run that cleans up\nthe TIME_WAIT connection. Consequently, the active connection count\ndrops to 0, which xt_connlimit mishandles, leading to the false rejection\nof the perfectly valid new connection.\n\nFix this by replacing the interface check with protocol-agnostic state\nchecks. We now skip the tree insertion and preserve the lockless garbage\ncollection optimization only if the connection is IPS_ASSURED. This\nallows early-confirmed setup packets (such as reused TIME_WAIT sockets\nor locally generated SYN-ACKs) to be properly evaluated and counted\nwithout falsely dropping. The goto check_connections path is maintained\nto ensure these setup packets are deduplicated correctly.\n\nThis has been tested with slowhttptest and HTTP server configured\nlocally to ensure we are not breaking soft-limiting scenarios for local\nor external connections. In addition, it was tested with a OVS zone\nlimit too.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72418.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":230303,"id":"CVE-2026-72418","ts":1793130916409,"field":"cvss","old":"5.5","new":"7.5"},{"seq":230302,"id":"CVE-2026-72418","ts":1793130916409,"field":"severity","old":"medium","new":"high"},{"seq":223625,"id":"CVE-2026-72418","ts":1792238340767,"field":"cvss","old":"7.5","new":"5.5"},{"seq":223624,"id":"CVE-2026-72418","ts":1792238340767,"field":"severity","old":"high","new":"medium"}]}