{"schema":"threatline.record/2","record":{"id":"CVE-2026-98643","aliases":[],"summary":"bpf: Fix out-of-bounds read of rtt_min in sock_ops","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix out-of-bounds read of rtt_min in sock_ops\n\nA sockops prog reading skops->rtt_min never checks the sk type: on the\ntcp_conn_request() path sock_ops->sk is a request_sock (non-full), and the\nctx rewrite casts it to a tcp_sock (full) and reads rtt_min past the end of\nthe request_sock, returning dirty adjacent memory.\n\n\tSEC(\"sockops\")\n\tint prog(struct bpf_sock_ops *skops)\n\t{\n\t\tswitch (skops->op) {\n\t\tcase BPF_SOCK_OPS_RWND_INIT:\n\t\t\tleak = skops->rtt_min;   /* reads the request_sock OOB */\n\t\t...\n\t\t}\n\t}\n\nFor instance one such read returned rtt_min=0xffff8881, the high half of a\nleaked kernel pointer.\n\nGuarding that cast is exactly what SOCK_OPS_GET_FIELD() does -- it checks\nis_locked_tcp_sock and returns 0 when sock_ops->sk is not a locked full\nsocket. Every other tcp_sock field in sock_ops goes through it; rtt_min is\nthe only one open-coded, so it skips the check.\n\nRead rtt_min through SOCK_OPS_GET_FIELD() too. rtt_min is a bit special:\nit is a struct minmax and we only want the current min, so pass\nrtt_min.s[0].v. That is equivalent to the old hand-computed offset\n\n\toffsetof(struct tcp_sock, rtt_min) + sizeof_field(struct minmax_sample, t)\n\n(s[0] sits at rtt_min + 0 and .v at + sizeof(.t), i.e. what minmax_get()\nreturns), so the loaded field is unchanged and only the full-sock guard is\nadded. The two BUILD_BUG_ON()s that protected the hand-computed offset\nare no longer needed.\n\nBefore patch:\n\n\t0: r1 = *(u64 *)(r1 +0)      ; r1 = skops->sk\n\t1: r1 = *(u32 *)(r1 +2324)   ; ((tcp_sock *)sk)->rtt_min.s[0].v\n\nAfter patch:\n\n\t0: *(u64 *)(r1 +56) = r9\n\t1: r9 = *(u8 *)(r1 +50)      ; is_locked_tcp_sock\n\t2: if r9 == 0 goto pc+4      ; not a locked full sock -> 0\n\t3: r9 = *(u64 *)(r1 +56)\n\t4: r1 = *(u64 *)(r1 +0)      ; r1 = skops->sk\n\t5: r1 = *(u32 *)(r1 +2324)   ; rtt_min.s[0].v\n\t6: goto pc+2\n\t7: r9 = *(u64 *)(r1 +56)\n\t8: r1 = 0","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98643","source_modified_at":"2026-10-19T09:23:12.946Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"44f0e43037d3a17b043843ba67610ac7c7e37db6","lessThan":"0c796efa919f52f788c22c79d1f1b70321696b3d","status":"affected","versionType":"git"},{"version":"44f0e43037d3a17b043843ba67610ac7c7e37db6","lessThan":"fc9d0e6e9d86fbefe7b8fe6ee49f4cf102add79d","status":"affected","versionType":"git"},{"version":"44f0e43037d3a17b043843ba67610ac7c7e37db6","lessThan":"fd6bf2721933d8c90bc4ce57f3e204c9295e7e3f","status":"affected","versionType":"git"},{"version":"44f0e43037d3a17b043843ba67610ac7c7e37db6","lessThan":"a8a9becbac93a9f54f4d565f1f3005eb08a7912f","status":"affected","versionType":"git"},{"version":"44f0e43037d3a17b043843ba67610ac7c7e37db6","lessThan":"3a46f14e6cf375f3ca38f8f6e6524749e24ea0a8","status":"affected","versionType":"git"},{"version":"44f0e43037d3a17b043843ba67610ac7c7e37db6","lessThan":"6785313d4fac96afb21ef193610c1fa88b1a9e64","status":"affected","versionType":"git"},{"version":"44f0e43037d3a17b043843ba67610ac7c7e37db6","lessThan":"cba54d142c43ec96d8c4d566f66439e8c0afded7","status":"affected","versionType":"git"},{"version":"44f0e43037d3a17b043843ba67610ac7c7e37db6","lessThan":"75f8cf22463d82bb1fb0239a3d485fc8f4c8ef03","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98643","source_modified_at":"2026-10-19T09:23:12.946Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"4.16","status":"affected"},{"version":"0","lessThan":"4.16","status":"unaffected","versionType":"semver"},{"version":"5.10.271","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.55","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.9","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98643","source_modified_at":"2026-10-19T09:23:12.946Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"0c796efa919f52f788c22c79d1f1b70321696b3d","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98643","source_modified_at":"2026-10-19T09:23:12.946Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"3a46f14e6cf375f3ca38f8f6e6524749e24ea0a8","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98643","source_modified_at":"2026-10-19T09:23:12.946Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6785313d4fac96afb21ef193610c1fa88b1a9e64","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98643","source_modified_at":"2026-10-19T09:23:12.946Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"75f8cf22463d82bb1fb0239a3d485fc8f4c8ef03","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.0021,"percentile":0.1072,"score_date":"2026-10-23"},"published_at":"2026-10-18T15:20:14.561Z","modified_at":"2026-10-19T09:23:12.946Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98643","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:23:12.946Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98643","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/0c796efa919f52f788c22c79d1f1b70321696b3d"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/fc9d0e6e9d86fbefe7b8fe6ee49f4cf102add79d"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/fd6bf2721933d8c90bc4ce57f3e204c9295e7e3f"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/a8a9becbac93a9f54f4d565f1f3005eb08a7912f"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/3a46f14e6cf375f3ca38f8f6e6524749e24ea0a8"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/6785313d4fac96afb21ef193610c1fa88b1a9e64"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/cba54d142c43ec96d8c4d566f66439e8c0afded7"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/75f8cf22463d82bb1fb0239a3d485fc8f4c8ef03"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:23:12.946Z","content_hash":"c45662baa0f5f4aa777a0ede1e5f8a4e83c146210667be1bd21b25c584802c99"}}