{"schema":"threatline.record/2","record":{"id":"CVE-2026-98049","aliases":[],"summary":"bpf: zero extend the result of an arena 32-bit cmpxchg","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: zero extend the result of an arena 32-bit cmpxchg\n\nbpf_convert_ctx_accesses() rewrites an atomic on an arena pointer from\nBPF_STX | BPF_ATOMIC to BPF_STX | BPF_PROBE_ATOMIC, and it runs before\nbpf_opt_subreg_zext_lo32_rnd_hi32().\n\nThat pass emits an explicit zero extension for a 32-bit cmpxchg even\nwhen bpf_jit_needs_zext() is false. This is done because on some\narchitectures 32-bit cmpxchg requires explicit zero extension for the\ndst register. E.g. on x86-64 'lock cmpxchg' does not change the %eax\nif comparison is successful, while BPF semantics declare that each\noperation on a 32-bit register zero extends it's upper half.\n\nis_cmpxchg_insn() matches BPF_MODE == BPF_ATOMIC only, so an arena\ncmpxchg misses said zero extension adjustment. This patch adjusts\nis_cmpxchg_insn() to match BPF_PROBE_ATOMIC alongside BPF_ATOMIC.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98049","source_modified_at":"2026-10-21T12:54:16.141Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"d503a04f8bc0c75dc9db9452d8cc79d748afb752","lessThan":"1bb1be18263995b159cf5afad3a05500ba6d2a7b","status":"affected","versionType":"git"},{"version":"d503a04f8bc0c75dc9db9452d8cc79d748afb752","lessThan":"6bb6ae5ab1beffda51dabf41612f501d07f10fc6","status":"affected","versionType":"git"},{"version":"d503a04f8bc0c75dc9db9452d8cc79d748afb752","lessThan":"1c1b476d43a8b6c9bc04600369dd8cc39950d98e","status":"affected","versionType":"git"},{"version":"d503a04f8bc0c75dc9db9452d8cc79d748afb752","lessThan":"4814ed6406f3493bd554ad046da5f7fc04833571","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98049","source_modified_at":"2026-10-21T12:54:16.141Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"6.10","status":"affected"},{"version":"0","lessThan":"6.10","status":"unaffected","versionType":"semver"},{"version":"6.12.114","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.57","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.7","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-2026-98049","source_modified_at":"2026-10-21T12:54:16.141Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"1bb1be18263995b159cf5afad3a05500ba6d2a7b","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98049","source_modified_at":"2026-10-21T12:54:16.141Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6bb6ae5ab1beffda51dabf41612f501d07f10fc6","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98049","source_modified_at":"2026-10-21T12:54:16.141Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"1c1b476d43a8b6c9bc04600369dd8cc39950d98e","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98049","source_modified_at":"2026-10-21T12:54:16.141Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"4814ed6406f3493bd554ad046da5f7fc04833571","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00122,"percentile":0.01828,"score_date":"2026-10-23"},"published_at":"2026-09-25T10:23:58.561Z","modified_at":"2026-10-21T12:54:16.141Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98049","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T12:54:16.141Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98049","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/1bb1be18263995b159cf5afad3a05500ba6d2a7b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/6bb6ae5ab1beffda51dabf41612f501d07f10fc6"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/1c1b476d43a8b6c9bc04600369dd8cc39950d98e"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/4814ed6406f3493bd554ad046da5f7fc04833571"}],"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":"2026-10-21T12:54:16.141Z","content_hash":"7278c330d98431b261c544b27d16f54e3b87989d6929c353b41d8bbcb716d7b4"}}