{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-31555", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-31555", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-04-24T14:35:39.211Z", "updatedAt": "2026-10-15T01:17:00.034Z", "importedAt": "2026-10-24T01:58:02.025Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "futex: Clear stale exiting pointer in futex_lock_pi() retry path", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Clear stale exiting pointer in futex_lock_pi() retry path\n\nFuzzying/stressing futexes triggered:\n\n WARNING: kernel/futex/core.c:825 at wait_for_owner_exiting+0x7a/0x80, CPU#11: futex_lock_pi_s/524\n\nWhen futex_lock_pi_atomic() sees the owner is exiting, it returns -EBUSY\nand stores a refcounted task pointer in 'exiting'.\n\nAfter wait_for_owner_exiting() consumes that reference, the local pointer\nis never reset to nil. Upon a retry, if futex_lock_pi_atomic() returns a\ndifferent error, the bogus pointer is passed to wait_for_owner_exiting().\n\n CPU0\t\t\t CPU1\t\t CPU2\n futex_lock_pi(uaddr)\n // acquires the PI futex\n exit()\n futex_cleanup_begin()\n futex_state = EXITING;\n\t\t\t futex_lock_pi(uaddr)\n\t\t\t futex_lock_pi_atomic()\n\t\t\t\t attach_to_pi_owner()\n\t\t\t\t // observes EXITING\n\t\t\t\t *exiting = owner; // takes ref\n\t\t\t\t return -EBUSY\n\t\t\t wait_for_owner_exiting(-EBUSY, owner)\n\t\t\t\t put_task_struct(); // drops ref\n\t\t\t // exiting still points to owner\n\t\t\t goto retry;\n\t\t\t futex_lock_pi_atomic()\n\t\t\t\t lock_pi_update_atomic()\n\t\t\t\t cmpxchg(uaddr)\n\t\t\t\t\t*uaddr ^= WAITERS // whatever\n\t\t\t\t // value changed\n\t\t\t\t return -EAGAIN;\n\t\t\t wait_for_owner_exiting(-EAGAIN, exiting) // stale\n\t\t\t\t WARN_ON_ONCE(exiting)\n\nFix this by resetting upon retry, essentially aligning it with requeue_pi.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "status": "affected", "versionType": "git", "lessThan": "33095ae3bdde5e5c264d7e88a2f3e7703a26c7aa" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "status": "affected", "versionType": "git", "lessThan": "e7824ec168d2ac883a213cd1f4d6cc0816002a85" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "status": "affected", "versionType": "git", "lessThan": "5e8e06bf8909e79b4acd950cf578cfc2f10bbefa" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "status": "affected", "versionType": "git", "lessThan": "de7c0c04ad868f2cee6671b11c0a6d20421af1da" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "status": "affected", "versionType": "git", "lessThan": "7475dfad10a05a5bfadebf5f2499bd61b19ed293" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "status": "affected", "versionType": "git", "lessThan": "92e47ad03e03dbb5515bdf06444bf6b1e147310d" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "status": "affected", "versionType": "git", "lessThan": "71112e62807d1925dc3ae6188b11f8cfc85aec23" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "status": "affected", "versionType": "git", "lessThan": "210d36d892de5195e6766c45519dfb1e65f3eb83" }, { "version": "f2a9957e5c08b1b1caacd18a3dc4c0a1bdb7b463", "status": "affected", "versionType": "git" }, { "version": "cf16e42709aa86aa3e37f3acc3d13d5715d90096", "status": "affected", "versionType": "git" }, { "version": "61fa9f167caaa73d0a7c88f498eceeb12c6fa3db", "status": "affected", "versionType": "git" }, { "version": "7874eee0130adf9bee28e8720bb5dd051089def3", "status": "affected", "versionType": "git" }, { "version": "fc3b55ef2c840bb2746b2d8121a0788de84f7fac", "status": "affected", "versionType": "git" }, { "version": "4.4.255", "status": "affected", "versionType": "semver", "lessThan": "4.5" }, { "version": "4.9.255", "status": "affected", "versionType": "semver", "lessThan": "4.10" }, { "version": "4.14.158", "status": "affected", "versionType": "semver", "lessThan": "4.15" }, { "version": "4.19.172", "status": "affected", "versionType": "semver", "lessThan": "4.20" }, { "version": "5.4.1", "status": "affected", "versionType": "semver", "lessThan": "5.5" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.5", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.5" }, { "version": "5.10.253", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.203", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.168", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.131", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.80", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.21", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "6.19.11", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.19.*" }, { "version": "7.0", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }