{"id":"CVE-2024-53143","state":"PUBLISHED","title":"fsnotify: Fix ordering of iput() and watched_objects decrement","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfsnotify: Fix ordering of iput() and watched_objects decrement\n\nEnsure the superblock is kept alive until we're done with iput().\nHolding a reference to an inode is not allowed unless we ensure the\nsuperblock stays alive, which fsnotify does by keeping the\nwatched_objects count elevated, so iput() must happen before the\nwatched_objects decrement.\nThis can lead to a UAF of something like sb->s_fs_info in tmpfs, but the\nUAF is hard to hit because race orderings that oops are more likely, thanks\nto the CHECK_DATA_CORRUPTION() block in generic_shutdown_super().\n\nAlso, ensure that fsnotify_put_sb_watched_objects() doesn't call\nfsnotify_sb_watched_objects() on a superblock that may have already been\nfreed, which would cause a UAF read of sb->s_fsnotify_info.","publishedAt":"2024-12-07T06:40:43.522Z","updatedAt":"2026-08-05T11:44:05.871Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d2f277e26f521ccf6fb438463b41dba6123caabe","status":"affected","lessThan":"45a8f8232a495221ed058191629f5c628f21601a","versionType":"git"},{"version":"d2f277e26f521ccf6fb438463b41dba6123caabe","status":"affected","lessThan":"83af1cfa10d9aafdabd06b3655e07727f373b434","versionType":"git"},{"version":"d2f277e26f521ccf6fb438463b41dba6123caabe","status":"affected","lessThan":"21d1b618b6b9da46c5116c640ac4b1cc8d40d63a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/notify/mark.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.11.11","status":"unaffected","lessThanOrEqual":"6.11.*","versionType":"semver"},{"version":"6.12.2","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/notify/mark.c"]}],"references":["https://git.kernel.org/stable/c/45a8f8232a495221ed058191629f5c628f21601a","https://git.kernel.org/stable/c/83af1cfa10d9aafdabd06b3655e07727f373b434","https://git.kernel.org/stable/c/21d1b618b6b9da46c5116c640ac4b1cc8d40d63a","https://project-zero.issues.chromium.org/issues/379667898"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:08:04.920Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2024/53xxx/CVE-2024-53143.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-53143","state":"PUBLISHED","datePublished":"2024-12-07T06:40:43.522Z","dateUpdated":"2026-08-05T11:44:05.871Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-11-19T17:17:24.997Z"},"containers":{"cna":{"title":"fsnotify: Fix ordering of iput() and watched_objects decrement","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfsnotify: Fix ordering of iput() and watched_objects decrement\n\nEnsure the superblock is kept alive until we're done with iput().\nHolding a reference to an inode is not allowed unless we ensure the\nsuperblock stays alive, which fsnotify does by keeping the\nwatched_objects count elevated, so iput() must happen before the\nwatched_objects decrement.\nThis can lead to a UAF of something like sb->s_fs_info in tmpfs, but the\nUAF is hard to hit because race orderings that oops are more likely, thanks\nto the CHECK_DATA_CORRUPTION() block in generic_shutdown_super().\n\nAlso, ensure that fsnotify_put_sb_watched_objects() doesn't call\nfsnotify_sb_watched_objects() on a superblock that may have already been\nfreed, which would cause a UAF read of sb->s_fsnotify_info."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d2f277e26f521ccf6fb438463b41dba6123caabe","status":"affected","lessThan":"45a8f8232a495221ed058191629f5c628f21601a","versionType":"git"},{"version":"d2f277e26f521ccf6fb438463b41dba6123caabe","status":"affected","lessThan":"83af1cfa10d9aafdabd06b3655e07727f373b434","versionType":"git"},{"version":"d2f277e26f521ccf6fb438463b41dba6123caabe","status":"affected","lessThan":"21d1b618b6b9da46c5116c640ac4b1cc8d40d63a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/notify/mark.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.11.11","status":"unaffected","lessThanOrEqual":"6.11.*","versionType":"semver"},{"version":"6.12.2","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/notify/mark.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/45a8f8232a495221ed058191629f5c628f21601a"},{"url":"https://git.kernel.org/stable/c/83af1cfa10d9aafdabd06b3655e07727f373b434"},{"url":"https://git.kernel.org/stable/c/21d1b618b6b9da46c5116c640ac4b1cc8d40d63a"},{"url":"https://project-zero.issues.chromium.org/issues/379667898"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached purely through local syscalls — inotify_init/inotify_add_watch/inotify_rm_watch on one side and mount/umount on the other. No network or remote peer input is involved.\nAC:L - The attacker owns both sides of the race: their own thread dropping the inotify mark and their own thread unmounting their own tmpfs in a private mount namespace, and the loop can be retried indefinitely with attacker-chosen heap grooming and CPU pinning to widen the window.\nPR:L - inotify_user.c has no capability checks at all, and tmpfs/ramfs/FUSE are FS_USERNS_MOUNT, so an unprivileged user gets the required mount and umount via unshare -Urm — per guidance, user-namespace-reachable is Low, not High.\nUI:N - A single unprivileged process drives the entire sequence — create the mount, add and remove the watch, and unmount — with no action by any other user.\nS:U - The corruption is of kernel slab objects (super_block, shmem_sb_info) within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The freed super_block and s_fs_info are read after free (SHMEM_SB(inode->i_sb) dereference, sb->s_fsnotify_info read), and since the attacker can reallocate those kmalloc slots with controlled data and observe the results, this is leverageable for kernel memory disclosure.\nI:H - The post-free path performs writes into freed memory — sbinfo->free_ispace accumulation, spin_lock acquisition, and list_del on the freed sb->s_inodes head — giving a groomable write primitive into attacker-reallocated slab objects suitable for control-flow hijacking.\nA:H - The most likely outcome is the CHECK_DATA_CORRUPTION(\"VFS: Busy inodes after unmount\") report, which is a BUG() with CONFIG_BUG_ON_DATA_CORRUPTION, and otherwise the use-after-free on a freed superblock reliably oopses the kernel."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T11:44:05.871Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.11.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.13"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.8,"attackVector":"LOCAL","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2024-12-11T14:22:39.197739Z","id":"CVE-2024-53143","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","type":"CWE","lang":"en","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-12-13T13:57:38.651Z"}}]}}}