{"api_version":"1","generated_at":"2026-07-03T23:46:02+00:00","cve":"CVE-2026-52977","urls":{"html":"https://cve.report/CVE-2026-52977","api":"https://cve.report/api/cve/CVE-2026-52977.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-52977","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-52977"},"summary":{"title":"futex: Prevent lockup in requeue-PI during signal/ timeout wakeup","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Prevent lockup in requeue-PI during signal/ timeout wakeup\n\nDuring wait-requeue-pi (task A) and requeue-PI (task B) the following\nrace can happen:\n\n     Task A                             Task B\n  futex_wait_requeue_pi()\n    futex_setup_timer()\n    futex_do_wait()\n                                   futex_requeue()\n                                        CLASS(hb, hb1)(&key1);\n                                        CLASS(hb, hb2)(&key2);\n        *timeout*\n    futex_requeue_pi_wakeup_sync()\n        requeue_state = Q_REQUEUE_PI_IGNORE\n\n    *blocks on hb->lock*\n\n                                        futex_proxy_trylock_atomic()\n                                          futex_requeue_pi_prepare()\n                                            Q_REQUEUE_PI_IGNORE => -EAGAIN\n                                        double_unlock_hb(hb1, hb2)\n                                         *retry*\n\nTask B acquires both hb locks and attempts to acquire the PI-lock of the\ntop most waiter (task B). Task A is leaving early due to a signal/\ntimeout and started removing itself from the queue. It updates its\nrequeue_state but can not remove it from the list because this requires\nthe hb lock which is owned by task B.\n\nUsually task A is able to swoop the lock after task B unlocked it.\nHowever if task B is of higher priority then task A may not be able to\nwake up in time and acquire the lock before task B gets it again.\nEspecially on a UP system where A is never scheduled.\n\nAs a result task A blocks on the lock and task B busy loops, trying to\nmake progress but live locks the system instead. Tragic.\n\nThis can be fixed by removing the top most waiter from the list in this\ncase. This allows task B to grab the next top waiter (if any) in the\nnext iteration and make progress.\n\nRemove the top most waiter if futex_requeue_pi_prepare() fails.\nLet the waiter conditionally remove itself from the list in\nhandle_early_requeue_pi_wakeup().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-06-24 17:17:08","updated_at":"2026-06-24 17:17:08"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/69a7cfc66405aeaa2483147653d031b3592ffc9c","name":"https://git.kernel.org/stable/c/69a7cfc66405aeaa2483147653d031b3592ffc9c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bc7304f3ae20972d11db6e0b1b541c63feda5f05","name":"https://git.kernel.org/stable/c/bc7304f3ae20972d11db6e0b1b541c63feda5f05","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e3f95b1ba242e37093305812df7fdbe7288a43ac","name":"https://git.kernel.org/stable/c/e3f95b1ba242e37093305812df7fdbe7288a43ac","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4e0ed44e51727d56244a822ab941efe507c47966","name":"https://git.kernel.org/stable/c/4e0ed44e51727d56244a822ab941efe507c47966","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0","name":"https://git.kernel.org/stable/c/0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0aacb6d18f76552e3e0ee25d9f40d21b3486f4cf","name":"https://git.kernel.org/stable/c/0aacb6d18f76552e3e0ee25d9f40d21b3486f4cf","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-52977","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-52977","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07d91ef510fb16a2e0ca7453222105835b7ba3b8 4e0ed44e51727d56244a822ab941efe507c47966 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07d91ef510fb16a2e0ca7453222105835b7ba3b8 e3f95b1ba242e37093305812df7fdbe7288a43ac git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07d91ef510fb16a2e0ca7453222105835b7ba3b8 0aacb6d18f76552e3e0ee25d9f40d21b3486f4cf git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07d91ef510fb16a2e0ca7453222105835b7ba3b8 69a7cfc66405aeaa2483147653d031b3592ffc9c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07d91ef510fb16a2e0ca7453222105835b7ba3b8 0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07d91ef510fb16a2e0ca7453222105835b7ba3b8 bc7304f3ae20972d11db6e0b1b541c63feda5f05 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.15","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.175 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.141 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.91 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.33 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.10 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"52977","cve":"CVE-2026-52977","epss":"0.001720000","percentile":"0.068950000","score_date":"2026-06-29","updated_at":"2026-06-30 00:06:55"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/futex/requeue.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"4e0ed44e51727d56244a822ab941efe507c47966","status":"affected","version":"07d91ef510fb16a2e0ca7453222105835b7ba3b8","versionType":"git"},{"lessThan":"e3f95b1ba242e37093305812df7fdbe7288a43ac","status":"affected","version":"07d91ef510fb16a2e0ca7453222105835b7ba3b8","versionType":"git"},{"lessThan":"0aacb6d18f76552e3e0ee25d9f40d21b3486f4cf","status":"affected","version":"07d91ef510fb16a2e0ca7453222105835b7ba3b8","versionType":"git"},{"lessThan":"69a7cfc66405aeaa2483147653d031b3592ffc9c","status":"affected","version":"07d91ef510fb16a2e0ca7453222105835b7ba3b8","versionType":"git"},{"lessThan":"0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0","status":"affected","version":"07d91ef510fb16a2e0ca7453222105835b7ba3b8","versionType":"git"},{"lessThan":"bc7304f3ae20972d11db6e0b1b541c63feda5f05","status":"affected","version":"07d91ef510fb16a2e0ca7453222105835b7ba3b8","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/futex/requeue.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.15"},{"lessThan":"5.15","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.175","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.141","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.91","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.33","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.175","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.141","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.91","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.33","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.10","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"5.15","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Prevent lockup in requeue-PI during signal/ timeout wakeup\n\nDuring wait-requeue-pi (task A) and requeue-PI (task B) the following\nrace can happen:\n\n     Task A                             Task B\n  futex_wait_requeue_pi()\n    futex_setup_timer()\n    futex_do_wait()\n                                   futex_requeue()\n                                        CLASS(hb, hb1)(&key1);\n                                        CLASS(hb, hb2)(&key2);\n        *timeout*\n    futex_requeue_pi_wakeup_sync()\n        requeue_state = Q_REQUEUE_PI_IGNORE\n\n    *blocks on hb->lock*\n\n                                        futex_proxy_trylock_atomic()\n                                          futex_requeue_pi_prepare()\n                                            Q_REQUEUE_PI_IGNORE => -EAGAIN\n                                        double_unlock_hb(hb1, hb2)\n                                         *retry*\n\nTask B acquires both hb locks and attempts to acquire the PI-lock of the\ntop most waiter (task B). Task A is leaving early due to a signal/\ntimeout and started removing itself from the queue. It updates its\nrequeue_state but can not remove it from the list because this requires\nthe hb lock which is owned by task B.\n\nUsually task A is able to swoop the lock after task B unlocked it.\nHowever if task B is of higher priority then task A may not be able to\nwake up in time and acquire the lock before task B gets it again.\nEspecially on a UP system where A is never scheduled.\n\nAs a result task A blocks on the lock and task B busy loops, trying to\nmake progress but live locks the system instead. Tragic.\n\nThis can be fixed by removing the top most waiter from the list in this\ncase. This allows task B to grab the next top waiter (if any) in the\nnext iteration and make progress.\n\nRemove the top most waiter if futex_requeue_pi_prepare() fails.\nLet the waiter conditionally remove itself from the list in\nhandle_early_requeue_pi_wakeup()."}],"providerMetadata":{"dateUpdated":"2026-06-24T16:28:53.937Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/4e0ed44e51727d56244a822ab941efe507c47966"},{"url":"https://git.kernel.org/stable/c/e3f95b1ba242e37093305812df7fdbe7288a43ac"},{"url":"https://git.kernel.org/stable/c/0aacb6d18f76552e3e0ee25d9f40d21b3486f4cf"},{"url":"https://git.kernel.org/stable/c/69a7cfc66405aeaa2483147653d031b3592ffc9c"},{"url":"https://git.kernel.org/stable/c/0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0"},{"url":"https://git.kernel.org/stable/c/bc7304f3ae20972d11db6e0b1b541c63feda5f05"}],"title":"futex: Prevent lockup in requeue-PI during signal/ timeout wakeup","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-52977","datePublished":"2026-06-24T16:28:53.937Z","dateReserved":"2026-06-09T07:44:35.376Z","dateUpdated":"2026-06-24T16:28:53.937Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-24 17:17:08","lastModifiedDate":"2026-06-24 17:17:08","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"52977","Ordinal":"1","Title":"futex: Prevent lockup in requeue-PI during signal/ timeout wakeu","CVE":"CVE-2026-52977","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"52977","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Prevent lockup in requeue-PI during signal/ timeout wakeup\n\nDuring wait-requeue-pi (task A) and requeue-PI (task B) the following\nrace can happen:\n\n     Task A                             Task B\n  futex_wait_requeue_pi()\n    futex_setup_timer()\n    futex_do_wait()\n                                   futex_requeue()\n                                        CLASS(hb, hb1)(&key1);\n                                        CLASS(hb, hb2)(&key2);\n        *timeout*\n    futex_requeue_pi_wakeup_sync()\n        requeue_state = Q_REQUEUE_PI_IGNORE\n\n    *blocks on hb->lock*\n\n                                        futex_proxy_trylock_atomic()\n                                          futex_requeue_pi_prepare()\n                                            Q_REQUEUE_PI_IGNORE => -EAGAIN\n                                        double_unlock_hb(hb1, hb2)\n                                         *retry*\n\nTask B acquires both hb locks and attempts to acquire the PI-lock of the\ntop most waiter (task B). Task A is leaving early due to a signal/\ntimeout and started removing itself from the queue. It updates its\nrequeue_state but can not remove it from the list because this requires\nthe hb lock which is owned by task B.\n\nUsually task A is able to swoop the lock after task B unlocked it.\nHowever if task B is of higher priority then task A may not be able to\nwake up in time and acquire the lock before task B gets it again.\nEspecially on a UP system where A is never scheduled.\n\nAs a result task A blocks on the lock and task B busy loops, trying to\nmake progress but live locks the system instead. Tragic.\n\nThis can be fixed by removing the top most waiter from the list in this\ncase. This allows task B to grab the next top waiter (if any) in the\nnext iteration and make progress.\n\nRemove the top most waiter if futex_requeue_pi_prepare() fails.\nLet the waiter conditionally remove itself from the list in\nhandle_early_requeue_pi_wakeup().","Type":"Description","Title":"futex: Prevent lockup in requeue-PI during signal/ timeout wakeu"}]}}}