{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89787","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.766Z","datePublished":"2026-09-16T08:48:24.403Z","dateUpdated":"2026-09-16T08:48:24.403Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-16T08:48:24.403Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: check dir entry fits before reading the hash trailer in ext4_search_dir()\n\nFor casefolded encrypted directories ext4 stores an 8-byte hash trailer\nafter the name (EXT4_DIRENT_HASHES()), at an offset derived from\nde->name_len.  On the sb_no_casefold_compat_fallback() path ext4_match()\nreads that trailer, but ext4_search_dir()'s by-hand pre-check only tests\nde->name + de->name_len <= dlimit, which proves the name fits, not the\nrounded trailer.  A crafted entry whose name ends at the block boundary\npasses the check while EXT4_DIRENT_HASHES(de) lands past the block end,\nso ext4_match() reads out of bounds on an ordinary lookup.  KASAN reports\nit as a use-after-free when the page after the directory block holds a\nfreed object:\n\n  BUG: KASAN: use-after-free in ext4_match (fs/ext4/namei.c:1435)\n  Read of size 4 at addr ffff888010458000 by task exploit\n  Call Trace:\n   ext4_match (fs/ext4/namei.c:1435)\n   ext4_search_dir (fs/ext4/namei.c:1470)\n   __ext4_find_entry (fs/ext4/namei.c:1268 fs/ext4/namei.c:1632)\n   ext4_lookup (fs/ext4/namei.c:1703 fs/ext4/namei.c:1769)\n   ...\n   filename_lookup (fs/namei.c:2842)\n   vfs_statx (fs/stat.c:353)\n   __do_sys_newfstatat (fs/stat.c:538)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n\nRequire, for hash-in-dirent directories, that the whole entry including\nthe rounded trailer fits before calling ext4_match().  This is the same\nbound ext4_check_dir_entry() already enforces via ext4_dir_rec_len(), so\nno well-formed entry is rejected.  The other caller, ext4_find_dest_de(),\nruns ext4_check_dir_entry() first and is unaffected."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/namei.c"],"versions":[{"version":"471fbbea7ff7061b2d6474665cb5a2ceb4fd6500","lessThan":"4d20106c536b73c4a8a02652dc85e35898baebf7","status":"affected","versionType":"git"},{"version":"471fbbea7ff7061b2d6474665cb5a2ceb4fd6500","lessThan":"61a395967de06edba58760e81907a272db749faa","status":"affected","versionType":"git"},{"version":"471fbbea7ff7061b2d6474665cb5a2ceb4fd6500","lessThan":"e94676a08af6312aa72d8a981232b281f9bcfcf5","status":"affected","versionType":"git"},{"version":"471fbbea7ff7061b2d6474665cb5a2ceb4fd6500","lessThan":"d8c184bec24b5a00ae96d704856d935eaded1685","status":"affected","versionType":"git"},{"version":"471fbbea7ff7061b2d6474665cb5a2ceb4fd6500","lessThan":"3933884bc3102898b458c53fbd1ac52eb9cdb8a4","status":"affected","versionType":"git"},{"version":"471fbbea7ff7061b2d6474665cb5a2ceb4fd6500","lessThan":"83663c0b739480c00cfe785675db87520ec484ed","status":"affected","versionType":"git"},{"version":"471fbbea7ff7061b2d6474665cb5a2ceb4fd6500","lessThan":"c7e6b863d298f56522d0d08554bbea7f142e6588","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/namei.c"],"versions":[{"version":"5.13","status":"affected"},{"version":"0","lessThan":"5.13","status":"unaffected","versionType":"semver"},{"version":"5.15.221","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.188","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.110","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.52","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.6","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","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":"5.13","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/4d20106c536b73c4a8a02652dc85e35898baebf7"},{"url":"https://git.kernel.org/stable/c/61a395967de06edba58760e81907a272db749faa"},{"url":"https://git.kernel.org/stable/c/e94676a08af6312aa72d8a981232b281f9bcfcf5"},{"url":"https://git.kernel.org/stable/c/d8c184bec24b5a00ae96d704856d935eaded1685"},{"url":"https://git.kernel.org/stable/c/3933884bc3102898b458c53fbd1ac52eb9cdb8a4"},{"url":"https://git.kernel.org/stable/c/83663c0b739480c00cfe785675db87520ec484ed"},{"url":"https://git.kernel.org/stable/c/c7e6b863d298f56522d0d08554bbea7f142e6588"}],"title":"ext4: check dir entry fits before reading the hash trailer in ext4_search_dir()","x_generator":{"engine":"bippy-1.2.0"}}}}