{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-44941","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-08-21T05:34:56.665Z","datePublished":"2024-08-26T11:20:45.678Z","dateUpdated":"2026-08-05T11:37:10.547Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:37:10.547Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to cover read extent cache access with lock\n\nsyzbot reports a f2fs bug as below:\n\nBUG: KASAN: slab-use-after-free in sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46\nRead of size 4 at addr ffff8880739ab220 by task syz-executor200/5097\n\nCPU: 0 PID: 5097 Comm: syz-executor200 Not tainted 6.9.0-rc6-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0x169/0x550 mm/kasan/report.c:488\n kasan_report+0x143/0x180 mm/kasan/report.c:601\n sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46\n do_read_inode fs/f2fs/inode.c:509 [inline]\n f2fs_iget+0x33e1/0x46e0 fs/f2fs/inode.c:560\n f2fs_nfs_get_inode+0x74/0x100 fs/f2fs/super.c:3237\n generic_fh_to_dentry+0x9f/0xf0 fs/libfs.c:1413\n exportfs_decode_fh_raw+0x152/0x5f0 fs/exportfs/expfs.c:444\n exportfs_decode_fh+0x3c/0x80 fs/exportfs/expfs.c:584\n do_handle_to_path fs/fhandle.c:155 [inline]\n handle_to_path fs/fhandle.c:210 [inline]\n do_handle_open+0x495/0x650 fs/fhandle.c:226\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nWe missed to cover sanity_check_extent_cache() w/ extent cache lock,\nso, below race case may happen, result in use after free issue.\n\n- f2fs_iget\n - do_read_inode\n  - f2fs_init_read_extent_tree\n  : add largest extent entry in to cache\n\t\t\t\t\t- shrink\n\t\t\t\t\t - f2fs_shrink_read_extent_tree\n\t\t\t\t\t  - __shrink_extent_tree\n\t\t\t\t\t   - __detach_extent_node\n\t\t\t\t\t   : drop largest extent entry\n  - sanity_check_extent_cache\n  : access et->largest w/o lock\n\nlet's refactor sanity_check_extent_cache() to avoid extent cache access\nand call it before f2fs_init_read_extent_tree() to fix this issue."}],"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 vulnerable code is reached through ordinary VFS syscalls (`open`/`stat`/`open_by_handle_at`) that instantiate an f2fs inode via `f2fs_iget()`->`do_read_inode()`, requiring a local account with access to a mounted f2fs filesystem. There is no remote or adjacent-network protocol handler on the path.\nAC:L - The attacker controls both sides of the race: they force the shrinker side by inflating extent-cache memory past the `f2fs_available_free_memory(READ_EXTENT_CACHE)` watermark so `f2fs_balance_fs_bg()`/`f2fs_shrink_scan()` run `f2fs_shrink_read_extent_tree()` continuously, and drive the iget side by repeatedly evicting and re-instantiating inodes. syzbot reproduced it in default configuration (`READ_EXTENT_CACHE` is set by `default_options()`).\nPR:L - No capability, owner, or privilege check exists anywhere on the `f2fs_lookup`/`f2fs_iget`/`do_read_inode`/`sanity_check_extent_cache ` path — any unprivileged user who can look up a file on an f2fs mount reaches it (e.g. any app on Android's f2fs `/data`).\nUI:N - The attacker performs the entire sequence with their own file operations and memory pressure against an already-mounted filesystem; no victim action is required.\nS:U - The corruption and its consequences are confined to the kernel's own memory and the local system's security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - This is a slab-use-after-free read of a freed `extent_tree`; the attacker can groom the freed slot with controlled data, and the leaked `largest` extent is then installed as the inode's read-extent mapping, redirecting file reads to arbitrary data blocks and disclosing other files' contents, while the `f2fs_warn` also prints freed heap contents to the log.\nI:H - Beyond the read, the `CP_ERROR_FLAG` branch writes into the freed object (`ei->len = 0; et->largest_updated = true;`), giving a write primitive into a reallocated slab object, and the poisoned extent mapping causes subsequent I/O to be directed at attacker-influenced block addresses — a UAF of this shape is leverageable for control-flow hijack.\nA:H - The confirmed KASAN slab-use-after-free crashes the kernel, and the garbage `largest.blk` additionally drives `f2fs_is_valid_blkaddr()` failure paths (`f2fs_handle_error`, `SBI_NEED_FSCK`, `dump_stack`) that panic the system under `errors=panic`/`CONFIG_F2FS_CHECK_FS`, and can be retriggered at will."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/extent_cache.c","fs/f2fs/f2fs.h","fs/f2fs/inode.c"],"versions":[{"version":"98e4da8ca301e062d79ae168c67e56f3c3de3ce4","lessThan":"263df78166d3a9609b97d28c34029bd01874cbb8","status":"affected","versionType":"git"},{"version":"98e4da8ca301e062d79ae168c67e56f3c3de3ce4","lessThan":"323ef20b5558b9d9fd10c1224327af6f11a8177d","status":"affected","versionType":"git"},{"version":"98e4da8ca301e062d79ae168c67e56f3c3de3ce4","lessThan":"d7409b05a64f212735f0d33f5f1602051a886eab","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/f2fs/extent_cache.c","fs/f2fs/f2fs.h","fs/f2fs/inode.c"],"versions":[{"version":"3.8","status":"affected"},{"version":"0","lessThan":"3.8","status":"unaffected","versionType":"semver"},{"version":"6.6.47","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.10.6","lessThanOrEqual":"6.10.*","status":"unaffected","versionType":"semver"},{"version":"6.11","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":"3.8","versionEndExcluding":"6.6.47"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.10.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.11"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/263df78166d3a9609b97d28c34029bd01874cbb8"},{"url":"https://git.kernel.org/stable/c/323ef20b5558b9d9fd10c1224327af6f11a8177d"},{"url":"https://git.kernel.org/stable/c/d7409b05a64f212735f0d33f5f1602051a886eab"}],"title":"f2fs: fix to cover read extent cache access with lock","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2024-44941","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-09-10T15:27:29.159607Z"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2024-09-12T17:33:04.422Z"}}]}}