{"id":"CVE-2026-64007","revision":null,"records":[{"revision":"fcc19b307ad249aa9e0ae62ed47552b9","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-64007","aliases":[],"title":"netfilter: synproxy: refresh tcphdr after skb_ensure_writable","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: synproxy: refresh tcphdr after skb_ensure_writable\n\nsynproxy_tstamp_adjust() rewrites the TCP timestamp option in place\nand then patches the TCP checksum via inet_proto_csum_replace4() on\nthe caller-supplied tcphdr pointer. Both ipv4_synproxy_hook() and\nipv6_synproxy_hook() obtain that pointer with skb_header_pointer()\nbefore calling in, so it may either alias skb->head directly or\npoint at the caller's on-stack _tcph buffer.\n\nBetween obtaining the pointer and using it, the function calls\nskb_ensure_writable(skb, optend), which on a cloned or non-linear\nskb invokes pskb_expand_head() and frees the old skb->head. After\nthat point the cached th is stale:\n\n caller (ipv[46]_synproxy_hook)\n th = skb_header_pointer(skb, ..., &_tcph)\n synproxy_tstamp_adjust(skb, protoff, th, ...)\n skb_ensure_writable(skb, optend)\n pskb_expand_head() /* kfree(old skb->head) */\n ...\n inet_proto_csum_replace4(&th->check, ...)\n /* writes into freed head, or\n into the caller's stack copy\n leaving the on-wire checksum\n stale */\n\nThe option bytes are written through skb->data and are fine; only\nthe checksum update goes through th and so lands in the wrong\nplace. The result is either a write into freed slab memory or a\npacket leaving with a checksum that does not match its payload.\n\nFix by re-deriving th from skb->data + protoff immediately after\nskb_ensure_writable() succeeds, so the subsequent checksum update\ntargets the linear, writable header.","state":0,"publishedAt":"2026-07-19T14:56:23.049+00:00","modifiedAt":"2026-10-19T20:28:08.086+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_synproxy_core.c\"\n ],\n \"versions\": [\n {\n \"version\": \"48b1de4c110a7afa4b85862f6c75af817db26fad\",\n \"lessThan\": \"9902a1058992de5d95656b64a3bd95c077f7ba2c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"48b1de4c110a7afa4b85862f6c75af817db26fad\",\n \"lessThan\": \"d3019c61799adc21811af4b521f11f3dc77f8e04\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"48b1de4c110a7afa4b85862f6c75af817db26fad\",\n \"lessThan\": \"dd206819f210522579010d889d45a9530bb494bc\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"48b1de4c110a7afa4b85862f6c75af817db26fad\",\n \"lessThan\": \"af2c22ccb1f621aff487ff47a040e38e058541e7\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"48b1de4c110a7afa4b85862f6c75af817db26fad\",\n \"lessThan\": \"c7f945f7da097245a2f8ed7775ce48421047ee96\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"48b1de4c110a7afa4b85862f6c75af817db26fad\",\n \"lessThan\": \"f0fea2b6d5453a11ad11713bbf37561b9b3a7edf\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"48b1de4c110a7afa4b85862f6c75af817db26fad\",\n \"lessThan\": \"a91887a5b6ee4b98dfbf1db657ed2b879430149e\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"48b1de4c110a7afa4b85862f6c75af817db26fad\",\n \"lessThan\": \"92170e6afe927ab2792a3f71902845789c8e31b1\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\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_synproxy_core.c\"\n ],\n \"versions\": [\n {\n \"version\": \"3.12\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"3.12\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.259\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.210\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.176\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.143\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.93\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.35\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.0.12\",\n \"lessThanOrEqual\": \"7.0.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.1\",\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:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/9902a1058992de5d95656b64a3bd95c077f7ba2c","https://git.kernel.org/stable/c/d3019c61799adc21811af4b521f11f3dc77f8e04","https://git.kernel.org/stable/c/dd206819f210522579010d889d45a9530bb494bc","https://git.kernel.org/stable/c/af2c22ccb1f621aff487ff47a040e38e058541e7","https://git.kernel.org/stable/c/c7f945f7da097245a2f8ed7775ce48421047ee96","https://git.kernel.org/stable/c/f0fea2b6d5453a11ad11713bbf37561b9b3a7edf","https://git.kernel.org/stable/c/a91887a5b6ee4b98dfbf1db657ed2b879430149e","https://git.kernel.org/stable/c/92170e6afe927ab2792a3f71902845789c8e31b1"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-64007","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-64007","identifiers":["CVE-2026-64007"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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Not a global EPSS backfill.","generation":"2026-11-08T18:47:41.4173610+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-08T18:47:41.417361+00:00","lastSuccessAt":"2026-11-08T18:47:41.7296264+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.7296273+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-16991eac9aa5423ca0d0a0955fbb9b20","complete":true,"records":13666,"lastAttemptAt":"2026-11-08T18:47:44.4093775+00:00","lastSuccessAt":"2026-11-08T17:47:45.702+00:00","error":null,"lastVerifiedAt":"2026-11-08T17:47:45.702+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-08T18:47:41.2273184+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.2273184+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-08T18:47:41.0199708+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.0199708+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-964c14035e6f0f6478b2870fad6a7ef9f6045876d4a12af2c2e514521e54b6af","complete":true,"records":3055,"lastAttemptAt":"2026-11-08T18:47:41.3406936+00:00","lastSuccessAt":"2026-11-08T11:07:12.1927025+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.3406936+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-f8647d7ba64b1ba0dfdc7130944766d5b36d5b77d18fff0c79e651a4cff3c2b9","complete":true,"records":231293,"lastAttemptAt":"2026-11-08T18:47:41.1240385+00:00","lastSuccessAt":"2026-11-08T11:06:56.2918717+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.1240385+00:00","snapshotPublishedAt":"2026-11-08T11:02:50+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}