{"api_version":"1","generated_at":"2026-10-31T11:10:11+00:00","cve":"CVE-2026-99179","urls":{"html":"https://cve.report/CVE-2026-99179","api":"https://cve.report/api/cve/CVE-2026-99179.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-99179","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-99179"},"summary":{"title":"watch_queue: Fix note pool publication race in watch_queue_set_size()","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-28 11:17:38","updated_at":"2026-10-30 13:21:51"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/811fb6d0b07605e8e8d93bde8748be4b3028809a","name":"https://git.kernel.org/stable/c/811fb6d0b07605e8e8d93bde8748be4b3028809a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9e73a6754457ffed8399b835552013b9363e51d1","name":"https://git.kernel.org/stable/c/9e73a6754457ffed8399b835552013b9363e51d1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5e531d62f1f8834faf7a4eed0d41105cf6570a8f","name":"https://git.kernel.org/stable/c/5e531d62f1f8834faf7a4eed0d41105cf6570a8f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6aaa6c1a1b61aae332d6e7e0083140b86ea51e14","name":"https://git.kernel.org/stable/c/6aaa6c1a1b61aae332d6e7e0083140b86ea51e14","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4b20867d80e7e91fb7db531f34035d91591ba405","name":"https://git.kernel.org/stable/c/4b20867d80e7e91fb7db531f34035d91591ba405","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f94c45f83e688e41dfe1b3a589806a0a25567260","name":"https://git.kernel.org/stable/c/f94c45f83e688e41dfe1b3a589806a0a25567260","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/da52e5fcb2cae6acdc0d5722ff83499f8232b9d1","name":"https://git.kernel.org/stable/c/da52e5fcb2cae6acdc0d5722ff83499f8232b9d1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2137d487b25eefa862be70de489b64f4c679fe1f","name":"https://git.kernel.org/stable/c/2137d487b25eefa862be70de489b64f4c679fe1f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-99179","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99179","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c73be61cede5882f9605a852414db559c0ebedfd 2137d487b25eefa862be70de489b64f4c679fe1f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c73be61cede5882f9605a852414db559c0ebedfd 6aaa6c1a1b61aae332d6e7e0083140b86ea51e14 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c73be61cede5882f9605a852414db559c0ebedfd 4b20867d80e7e91fb7db531f34035d91591ba405 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c73be61cede5882f9605a852414db559c0ebedfd da52e5fcb2cae6acdc0d5722ff83499f8232b9d1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.224 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.191 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.161 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.115 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.59 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.13 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"99179","cve":"CVE-2026-99179","epss":"0.001720000","percentile":"0.066440000","score_date":"2026-10-30","updated_at":"2026-10-31 00:01:13"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/watch_queue.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"2137d487b25eefa862be70de489b64f4c679fe1f","status":"affected","version":"c73be61cede5882f9605a852414db559c0ebedfd","versionType":"git"},{"lessThan":"6aaa6c1a1b61aae332d6e7e0083140b86ea51e14","status":"affected","version":"c73be61cede5882f9605a852414db559c0ebedfd","versionType":"git"},{"lessThan":"4b20867d80e7e91fb7db531f34035d91591ba405","status":"affected","version":"c73be61cede5882f9605a852414db559c0ebedfd","versionType":"git"},{"lessThan":"da52e5fcb2cae6acdc0d5722ff83499f8232b9d1","status":"affected","version":"c73be61cede5882f9605a852414db559c0ebedfd","versionType":"git"},{"lessThan":"f94c45f83e688e41dfe1b3a589806a0a25567260","status":"affected","version":"c73be61cede5882f9605a852414db559c0ebedfd","versionType":"git"},{"lessThan":"811fb6d0b07605e8e8d93bde8748be4b3028809a","status":"affected","version":"c73be61cede5882f9605a852414db559c0ebedfd","versionType":"git"},{"lessThan":"9e73a6754457ffed8399b835552013b9363e51d1","status":"affected","version":"c73be61cede5882f9605a852414db559c0ebedfd","versionType":"git"},{"lessThan":"5e531d62f1f8834faf7a4eed0d41105cf6570a8f","status":"affected","version":"c73be61cede5882f9605a852414db559c0ebedfd","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/watch_queue.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.8"},{"lessThan":"5.8","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.273","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.224","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.191","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.161","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.115","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.59","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.13","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.273","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.224","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.191","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.161","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.115","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.59","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.13","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"5.8","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-10-30T12:42:42.438Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2137d487b25eefa862be70de489b64f4c679fe1f"},{"url":"https://git.kernel.org/stable/c/6aaa6c1a1b61aae332d6e7e0083140b86ea51e14"},{"url":"https://git.kernel.org/stable/c/4b20867d80e7e91fb7db531f34035d91591ba405"},{"url":"https://git.kernel.org/stable/c/da52e5fcb2cae6acdc0d5722ff83499f8232b9d1"},{"url":"https://git.kernel.org/stable/c/f94c45f83e688e41dfe1b3a589806a0a25567260"},{"url":"https://git.kernel.org/stable/c/811fb6d0b07605e8e8d93bde8748be4b3028809a"},{"url":"https://git.kernel.org/stable/c/9e73a6754457ffed8399b835552013b9363e51d1"},{"url":"https://git.kernel.org/stable/c/5e531d62f1f8834faf7a4eed0d41105cf6570a8f"}],"title":"watch_queue: Fix note pool publication race in watch_queue_set_size()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-99179","datePublished":"2026-10-28T10:35:32.734Z","dateReserved":"2026-09-25T10:25:14.399Z","dateUpdated":"2026-10-30T12:42:42.438Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-28 11:17:38","lastModifiedDate":"2026-10-30 13:21:51","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"99179","Ordinal":"1","Title":"watch_queue: Fix note pool publication race in watch_queue_set_s","CVE":"CVE-2026-99179","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"99179","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"watch_queue: Fix note pool publication race in watch_queue_set_s"}]}}}