{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31555", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.115Z", "datePublished": "2026-04-24T14:35:39.211Z", "dateUpdated": "2026-10-15T01:17:00.034Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-23T16:05:19.706Z" }, "descriptions": [ { "lang": "en", "value": "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": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/futex/pi.c" ], "versions": [ { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "lessThan": "33095ae3bdde5e5c264d7e88a2f3e7703a26c7aa", "status": "affected", "versionType": "git" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "lessThan": "e7824ec168d2ac883a213cd1f4d6cc0816002a85", "status": "affected", "versionType": "git" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "lessThan": "5e8e06bf8909e79b4acd950cf578cfc2f10bbefa", "status": "affected", "versionType": "git" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "lessThan": "de7c0c04ad868f2cee6671b11c0a6d20421af1da", "status": "affected", "versionType": "git" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "lessThan": "7475dfad10a05a5bfadebf5f2499bd61b19ed293", "status": "affected", "versionType": "git" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "lessThan": "92e47ad03e03dbb5515bdf06444bf6b1e147310d", "status": "affected", "versionType": "git" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "lessThan": "71112e62807d1925dc3ae6188b11f8cfc85aec23", "status": "affected", "versionType": "git" }, { "version": "3ef240eaff36b8119ac9e2ea17cbf41179c930ba", "lessThan": "210d36d892de5195e6766c45519dfb1e65f3eb83", "status": "affected", "versionType": "git" }, { "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", "lessThan": "4.5", "status": "affected", "versionType": "semver" }, { "version": "4.9.255", "lessThan": "4.10", "status": "affected", "versionType": "semver" }, { "version": "4.14.158", "lessThan": "4.15", "status": "affected", "versionType": "semver" }, { "version": "4.19.172", "lessThan": "4.20", "status": "affected", "versionType": "semver" }, { "version": "5.4.1", "lessThan": "5.5", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/futex/pi.c" ], "versions": [ { "version": "5.5", "status": "affected" }, { "version": "0", "lessThan": "5.5", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.253", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.203", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.168", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.131", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.80", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.21", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.11", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.10.253" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.15.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.1.168" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.6.131" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.12.80" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.18.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.19.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "7.0" }, { "vulnerable": true, "criteria": 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"https://git.kernel.org/stable/c/7475dfad10a05a5bfadebf5f2499bd61b19ed293" }, { "url": "https://git.kernel.org/stable/c/92e47ad03e03dbb5515bdf06444bf6b1e147310d" }, { "url": "https://git.kernel.org/stable/c/71112e62807d1925dc3ae6188b11f8cfc85aec23" }, { "url": "https://git.kernel.org/stable/c/210d36d892de5195e6766c45519dfb1e65f3eb83" } ], "title": "futex: Clear stale exiting pointer in futex_lock_pi() retry path", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-10-15T01:17:00.034Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", 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