{"id":"CVE-2026-72418","revision":"19878baa7a164487b9981ee3bedc8aa7","records":[{"revision":"19878baa7a164487b9981ee3bedc8aa7","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-72418","aliases":[],"title":"netfilter: nf_conncount: prevent connlimit drops for early confirmed ct","description":"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\") 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.","state":0,"publishedAt":"2026-08-15T05:56:38.374+00:00","modifiedAt":"2026-10-16T18:55:22.66+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/netfilter/nf_conncount.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"460c112e1d887b58b06b56e8e0230058906ff2c3\",\n                            \"lessThan\": \"000ac6830b56499d6b65fd91486ce6689eb02be4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"53bc0ac47f4f7621c991807bc90e01df49561ac8\",\n                            \"lessThan\": \"cbe2d14a7c5b1fc71821fbfee5c4963917411e92\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"ca8b4d1d6304a84ce2016fa2fe9a114b9607b839\",\n                            \"lessThan\": \"3793d24de224943e0a6016bbeffb6f5c4cea2e3d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"8286c02fe9100330475331253fc590f047963f90\",\n                            \"lessThan\": \"abef7f817217fcb62c11821d6b895063eadb2828\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"b29ddccf36946a90323486221f39e9f88cc01b8e\",\n                            \"lessThan\": \"ebfe8249ba79e4ff0f1e3aad8787b992ef27f026\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"77ea3d8ac3d3d59b5ac9ad639e4ba107c0f2ff1e\",\n                            \"lessThan\": \"329f2626ee5cb8fafdf6b58b624311529c57cb45\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"69894e5b4c5e28cda5f32af33d4a92b7a4b93b0e\",\n                            \"lessThan\": \"be52572c6d55f677ba76869d3c63805c0d4891a3\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"69894e5b4c5e28cda5f32af33d4a92b7a4b93b0e\",\n                            \"lessThan\": \"c8b6f36f766991e3ebebec6596daee4b04dcbc49\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f85623af16b83615e5f64a9b19ae1d584805cb07\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5.10.248\",\n                            \"lessThan\": \"5.10.261\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.198\",\n                            \"lessThan\": \"5.15.212\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.160\",\n                            \"lessThan\": \"6.1.178\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.120\",\n                            \"lessThan\": \"6.6.145\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.63\",\n                            \"lessThan\": \"6.12.97\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.2\",\n                            \"lessThan\": \"6.18.40\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.17.13\",\n                            \"lessThan\": \"6.18\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/netfilter/nf_conncount.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.19\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.19\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.261\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.212\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.178\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.145\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.97\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.40\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.5\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/000ac6830b56499d6b65fd91486ce6689eb02be4","https://git.kernel.org/stable/c/cbe2d14a7c5b1fc71821fbfee5c4963917411e92","https://git.kernel.org/stable/c/3793d24de224943e0a6016bbeffb6f5c4cea2e3d","https://git.kernel.org/stable/c/abef7f817217fcb62c11821d6b895063eadb2828","https://git.kernel.org/stable/c/ebfe8249ba79e4ff0f1e3aad8787b992ef27f026","https://git.kernel.org/stable/c/329f2626ee5cb8fafdf6b58b624311529c57cb45","https://git.kernel.org/stable/c/be52572c6d55f677ba76869d3c63805c0d4891a3","https://git.kernel.org/stable/c/c8b6f36f766991e3ebebec6596daee4b04dcbc49"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72418","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-72418","identifiers":["CVE-2026-72418"]},"retained":false,"historicalAffected":[]}],"coverage":[]}