{ "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-2026-92503", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-92503", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-09-17T16:10:16.062Z", "updatedAt": "2026-10-21T12:51:44.628Z", "importedAt": "2026-10-24T01:58:35.090Z", "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": "ext4: fix ABBA deadlock in ext4_xattr_inode_cache_find()", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix ABBA deadlock in ext4_xattr_inode_cache_find()\n\nSyzbot/stress-ng reported an ABBA deadlock in ext4 when exercising\nconcurrent xattr workloads (using the ea_inode mount/format option).\n\nThe deadlock occurs between the running transaction and the eviction\nthread:\n- Task 1 (stress-ng): Holds a reference to a shared mbcache_entry (ce)\n and calls ext4_xattr_inode_cache_find() -> ext4_iget() to retrieve\n the corresponding EA inode. Since the EA inode is currently being\n evicted, ext4_iget() blocks in __wait_on_freeing_inode() waiting for\n eviction to complete.\n- Task 2 (eviction thread): Currently evicting the same EA inode in\n ext4_evict_ea_inode(). It calls mb_cache_entry_wait_unused(oe) which\n blocks waiting for Task 1 to release the reference to the mbcache_entry.\n\nTo break this deadlock, implement a new ext4_iget() configuration flag\nnamed EXT4_IGET_NOWAIT. When set, perform a non-blocking lookup of the\ninode via VFS's find_inode_nowait() API.\n\nIf the inode is currently being evicted (marked with I_FREEING or\nI_WILL_FREE) or created (I_CREATING), or if it is not present in the VFS\ninode cache (cache miss), simply skip it (returning -ENOENT) rather than\nwaiting for eviction/creation to complete, breaking the ABBA cycle.\n\nSince we return -ENOENT immediately on a cache miss, we never attempt to\nallocate a new inode or call iget_locked(), completely eliminating any\nTOCTOU race window.\n\nIf the returned inode is I_NEW, wait for its initialization to clear via\nwait_on_new_inode(). If initialization fails and the inode is unhashed\nduring wait_on_new_inode() waking up (e.g., due to an I/O read error in\nanother thread), safely drop the reference and return -ENOENT. This\nunhashed check is executed unconditionally on all cache-hit pathways to\nproperly handle concurrent initialization failures.\n\nFinally, standard validation checks (including is_bad_inode,\nEXT4_EA_INODE_FL, file_acl, and xattr flags) are executed as normal inside\ncheck_igot_inode() to fully guarantee VFS-layer safety.\n\nIn ext4_xattr_inode_cache_find(), invoke ext4_iget() with the new\nEXT4_IGET_NOWAIT flag to perform the non-blocking cache search.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "737fb7853acd5bc8984f6f42e4bfba3334be8ae1", "status": "affected", "versionType": "git", "lessThan": "29a2a166450a3e89f61a486033b10cf170fde8b0" }, { "version": "0a46ef234756dca04623b7591e8ebb3440622f0b", "status": "affected", "versionType": "git", "lessThan": "d3b19b318e0e0483180d15f1d9f5e807a1fb59d5" }, { "version": "0a46ef234756dca04623b7591e8ebb3440622f0b", "status": "affected", "versionType": "git", "lessThan": "074d0620401974cbfa9b63684cdfae99c7b2059c" }, { "version": "0a46ef234756dca04623b7591e8ebb3440622f0b", "status": "affected", "versionType": "git", "lessThan": "7720fddd1fe344d14be258a2028f74ebf1569511" }, { "version": "0a46ef234756dca04623b7591e8ebb3440622f0b", "status": "affected", "versionType": "git", "lessThan": "03438084a7b8621fb5c762dd3d04cff5f2630fb2" }, { "version": "0752e7fb549d90c33b4d4186f11cfd25a556d1dd", "status": "affected", "versionType": "git" }, { "version": "111103907234bffd0a34fba070ad9367de058752", "status": "affected", "versionType": "git" }, { "version": "6.6.47", "status": "affected", "versionType": "semver", "lessThan": "6.6.160" }, { "version": "6.1.107", "status": "affected", "versionType": "semver", "lessThan": "6.2" }, { "version": "6.9.7", "status": "affected", "versionType": "semver", "lessThan": "6.10" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "6.10", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "6.10" }, { "version": "6.6.160", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.114", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.57", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.2.6", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.2.*" }, { "version": "7.3", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }