{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53838","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-12-09T01:27:17.826Z","datePublished":"2025-12-09T01:29:54.419Z","dateUpdated":"2026-08-05T09:16:21.177Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T09:16:21.177Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: synchronize atomic write aborts\n\nTo fix a race condition between atomic write aborts, I use the inode\nlock and make COW inode to be re-usable thoroughout the whole\natomic file inode lifetime."}],"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 race is driven entirely through local syscalls — `ioctl(F2FS_IOC_START_ATOMIC_WRITE/ABORT_ATOMIC_WRITE)` and `close()` — on a file residing on a mounted f2fs filesystem. No network or physical access is involved.\nAC:L - The attacker owns both sides of the race: it issues the unlocked `->release` abort from its own `close()` in one thread while issuing the `inode_lock`-held abort ioctl from another, and can retry the loop indefinitely at no cost. The `inode_lock` provides no exclusion against the release path, so the window is wide and deterministic to hit.\nPR:L - `__f2fs_ioctl` gates the atomic-write ioctls only on `inode_owner_or_capable()`, which any unprivileged local user satisfies for a file they created on an f2fs mount (e.g. any Android app under /data). No capability, mount option, or crafted image is required.\nUI:N - The attacker performs every step itself — create file, start atomic write, race close against the abort ioctl. No victim action or cooperating process is needed; f2fs simply being mounted is an environmental default, not user interaction.\nS:U - The corruption stays within the kernel's own security authority — a freed `struct inode` in `f2fs_inode_cachep`. There is no VM, IOMMU, or sandbox boundary crossed.\nC:H - The double `iput()` frees the COW `struct inode` while another thread still dereferences it, and `prepare_atomic_write_begin()` continues reading through the dangling `fi->cow_inode`. Reclaiming the freed slot with attacker-groomed objects gives an arbitrary kernel read primitive and leaks the contents of adjacent inodes.\nI:H - The losing thread performs `clear_bit()` and a dirty-list insertion into freed memory plus a second `iput()`, producing a double-free and refcount underflow on an inode object that embeds `i_op`, `i_fop`, and `a_ops` function-pointer tables — a classic write/control-flow-hijack primitive, alongside on-disk metadata corruption from the double evict.\nA:H - Even unexploited, the race yields inode refcount underflow, slab double-free, list corruption, and NULL/wild-pointer dereference via `F2FS_I(NULL)->flags`, all of which oops or panic the kernel. The attacker can trigger it repeatedly from an unprivileged loop."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/file.c","fs/f2fs/inode.c","fs/f2fs/segment.c","fs/f2fs/super.c"],"versions":[{"version":"3db1de0e582c358dd013f3703cd55b5fe4076436","lessThan":"102b82708c1523b36d421cb8687746906069bc17","status":"affected","versionType":"git"},{"version":"3db1de0e582c358dd013f3703cd55b5fe4076436","lessThan":"b7724360714642099cec907f54f42e55f5325453","status":"affected","versionType":"git"},{"version":"3db1de0e582c358dd013f3703cd55b5fe4076436","lessThan":"a46bebd502fe1a3bd1d22f64cedd93e7e7702693","status":"affected","versionType":"git"},{"version":"6db52f1944417c2601182a591a704e2f119c5215","status":"affected","versionType":"git"},{"version":"5.18.18","lessThan":"5.19","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/file.c","fs/f2fs/inode.c","fs/f2fs/segment.c","fs/f2fs/super.c"],"versions":[{"version":"5.19","status":"affected"},{"version":"0","lessThan":"5.19","status":"unaffected","versionType":"semver"},{"version":"6.1.18","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.2.5","lessThanOrEqual":"6.2.*","status":"unaffected","versionType":"semver"},{"version":"6.3","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":"5.19","versionEndExcluding":"6.1.18"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.2.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18.18"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/102b82708c1523b36d421cb8687746906069bc17"},{"url":"https://git.kernel.org/stable/c/b7724360714642099cec907f54f42e55f5325453"},{"url":"https://git.kernel.org/stable/c/a46bebd502fe1a3bd1d22f64cedd93e7e7702693"}],"title":"f2fs: synchronize atomic write aborts","x_generator":{"engine":"bippy-1.2.0"}}}}