{"schema":"threatline.record/2","record":{"id":"CVE-2026-99179","aliases":[],"summary":"watch_queue: Fix note pool publication race in watch_queue_set_size()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nwatch_queue: Fix note pool publication race in watch_queue_set_size()\n\nThere is a race between watch_queue_set_size() and post_one_notification().\nwatch_queue_set_size() publishes wqueue->notes, notes_bitmap, nr_pages and\nnr_notes with plain stores, and post_one_notification() reads them with\nplain loads under a different lock, so nothing orders the four stores\nagainst the poster's loads: depending on the build, notes can be stored\nlast (gcc 14 on x86-64 does this).  Since keyctl_watch_key() lets a watch\nattach to a queue before it is sized, post_one_notification() can already\nbe running on another CPU at that moment: it reads nr_notes > 0, passes\nits bounds check, and then reads notes while it is still NULL,\ndereferencing notes[0].\n\nAn unprivileged user triggers this reliably by watching one of its own\nkeys through a notification pipe and racing ioctl(IOC_WATCH_QUEUE_SET_SIZE)\non that pipe against keyctl(KEYCTL_SETPERM) on the key from another CPU,\ntriggering:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n  RIP: 0010:post_one_notification.isra.0+0xa2/0x1e0\n  Call Trace:\n   __post_watch_notification+0x148/0x180\n   keyctl_setperm_key+0x119/0x130\n   do_syscall_64+0x108/0x4c0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nFix this by publishing nr_notes last with smp_store_release(), and by\nreading it once with smp_load_acquire() in post_one_notification() before\nthe bitmap and the page array are touched.  A poster that observes a\nnon-zero nr_notes then also observes the pool behind it; one that observes\nzero drops the notification as before.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99179","source_modified_at":"2026-10-28T10:35:32.734Z","fetched_at":"2026-10-28T15:55:58.673066Z","product":"Linux","vendor":"Linux","versions":[{"version":"c73be61cede5882f9605a852414db559c0ebedfd","lessThan":"811fb6d0b07605e8e8d93bde8748be4b3028809a","status":"affected","versionType":"git"},{"version":"c73be61cede5882f9605a852414db559c0ebedfd","lessThan":"9e73a6754457ffed8399b835552013b9363e51d1","status":"affected","versionType":"git"},{"version":"c73be61cede5882f9605a852414db559c0ebedfd","lessThan":"5e531d62f1f8834faf7a4eed0d41105cf6570a8f","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99179","source_modified_at":"2026-10-28T10:35:32.734Z","fetched_at":"2026-10-28T15:55:58.673066Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.8","status":"affected"},{"version":"0","lessThan":"5.8","status":"unaffected","versionType":"semver"},{"version":"6.18.59","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.13","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-2026-99179","source_modified_at":"2026-10-28T10:35:32.734Z","fetched_at":"2026-10-28T15:55:58.673066Z","package":{"name":"Linux","ecosystem":null},"version":"811fb6d0b07605e8e8d93bde8748be4b3028809a","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99179","source_modified_at":"2026-10-28T10:35:32.734Z","fetched_at":"2026-10-28T15:55:58.673066Z","package":{"name":"Linux","ecosystem":null},"version":"9e73a6754457ffed8399b835552013b9363e51d1","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99179","source_modified_at":"2026-10-28T10:35:32.734Z","fetched_at":"2026-10-28T15:55:58.673066Z","package":{"name":"Linux","ecosystem":null},"version":"5e531d62f1f8834faf7a4eed0d41105cf6570a8f","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":null,"percentile":null,"score_date":null},"published_at":"2026-10-28T10:35:32.734Z","modified_at":"2026-10-28T10:35:32.734Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-99179","fetched_at":"2026-10-28T15:55:58.673066Z","source_modified_at":"2026-10-28T10:35:32.734Z"}],"sources":["CVE List"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/811fb6d0b07605e8e8d93bde8748be4b3028809a"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/9e73a6754457ffed8399b835552013b9363e51d1"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/5e531d62f1f8834faf7a4eed0d41105cf6570a8f"}],"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":"2026-10-28T10:35:32.734Z","content_hash":"e09e0a33e4811fbbef95937135d97b291c289265748f677ec0dc5a9c3ea0dcd6"}}