{"id":"CVE-2024-53178","state":"PUBLISHED","title":"smb: Don't leak cfid when reconnect races with open_cached_dir","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: Don't leak cfid when reconnect races with open_cached_dir\n\nopen_cached_dir() may either race with the tcon reconnection even before\ncompound_send_recv() or directly trigger a reconnection via\nSMB2_open_init() or SMB_query_info_init().\n\nThe reconnection process invokes invalidate_all_cached_dirs() via\ncifs_mark_open_files_invalid(), which removes all cfids from the\ncfids->entries list but doesn't drop a ref if has_lease isn't true. This\nresults in the currently-being-constructed cfid not being on the list,\nbut still having a refcount of 2. It leaks if returned from\nopen_cached_dir().\n\nFix this by setting cfid->has_lease when the ref is actually taken; the\ncfid will not be used by other threads until it has a valid time.\n\nAddresses these kmemleaks:\n\nunreferenced object 0xffff8881090c4000 (size 1024):\n  comm \"bash\", pid 1860, jiffies 4295126592\n  hex dump (first 32 bytes):\n    00 01 00 00 00 00 ad de 22 01 00 00 00 00 ad de  ........\".......\n    00 ca 45 22 81 88 ff ff f8 dc 4f 04 81 88 ff ff  ..E\"......O.....\n  backtrace (crc 6f58c20f):\n    [<ffffffff8b895a1e>] __kmalloc_cache_noprof+0x2be/0x350\n    [<ffffffff8bda06e3>] open_cached_dir+0x993/0x1fb0\n    [<ffffffff8bdaa750>] cifs_readdir+0x15a0/0x1d50\n    [<ffffffff8b9a853f>] iterate_dir+0x28f/0x4b0\n    [<ffffffff8b9a9aed>] __x64_sys_getdents64+0xfd/0x200\n    [<ffffffff8cf6da05>] do_syscall_64+0x95/0x1a0\n    [<ffffffff8d00012f>] entry_SYSCALL_64_after_hwframe+0x76/0x7e\nunreferenced object 0xffff8881044fdcf8 (size 8):\n  comm \"bash\", pid 1860, jiffies 4295126592\n  hex dump (first 8 bytes):\n    00 cc cc cc cc cc cc cc                          ........\n  backtrace (crc 10c106a9):\n    [<ffffffff8b89a3d3>] __kmalloc_node_track_caller_noprof+0x363/0x480\n    [<ffffffff8b7d7256>] kstrdup+0x36/0x60\n    [<ffffffff8bda0700>] open_cached_dir+0x9b0/0x1fb0\n    [<ffffffff8bdaa750>] cifs_readdir+0x15a0/0x1d50\n    [<ffffffff8b9a853f>] iterate_dir+0x28f/0x4b0\n    [<ffffffff8b9a9aed>] __x64_sys_getdents64+0xfd/0x200\n    [<ffffffff8cf6da05>] do_syscall_64+0x95/0x1a0\n    [<ffffffff8d00012f>] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nAnd addresses these BUG splats when unmounting the SMB filesystem:\n\nBUG: Dentry ffff888140590ba0{i=1000000000080,n=/}  still in use (2) [unmount of cifs cifs]\nWARNING: CPU: 3 PID: 3433 at fs/dcache.c:1536 umount_check+0xd0/0x100\nModules linked in:\nCPU: 3 UID: 0 PID: 3433 Comm: bash Not tainted 6.12.0-rc4-g850925a8133c-dirty #49\nHardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020\nRIP: 0010:umount_check+0xd0/0x100\nCode: 8d 7c 24 40 e8 31 5a f4 ff 49 8b 54 24 40 41 56 49 89 e9 45 89 e8 48 89 d9 41 57 48 89 de 48 c7 c7 80 e7 db ac e8 f0 72 9a ff <0f> 0b 58 31 c0 5a 5b 5d 41 5c 41 5d 41 5e 41 5f e9 2b e5 5d 01 41\nRSP: 0018:ffff88811cc27978 EFLAGS: 00010286\nRAX: 0000000000000000 RBX: ffff888140590ba0 RCX: ffffffffaaf20bae\nRDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff8881f6fb6f40\nRBP: ffff8881462ec000 R08: 0000000000000001 R09: ffffed1023984ee3\nR10: ffff88811cc2771f R11: 00000000016cfcc0 R12: ffff888134383e08\nR13: 0000000000000002 R14: ffff8881462ec668 R15: ffffffffaceab4c0\nFS:  00007f23bfa98740(0000) GS:ffff8881f6f80000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000556de4a6f808 CR3: 0000000123c80000 CR4: 0000000000350ef0\nCall Trace:\n <TASK>\n d_walk+0x6a/0x530\n shrink_dcache_for_umount+0x6a/0x200\n generic_shutdown_super+0x52/0x2a0\n kill_anon_super+0x22/0x40\n cifs_kill_sb+0x159/0x1e0\n deactivate_locked_super+0x66/0xe0\n cleanup_mnt+0x140/0x210\n task_work_run+0xfb/0x170\n syscall_exit_to_user_mode+0x29f/0x2b0\n do_syscall_64+0xa1/0x1a0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\nRIP: 0033:0x7f23bfb93ae7\nCode: ff ff ff ff c3 66 0f 1f 44 00 00 48 8b 0d 11 93 0d 00 f7 d8 64 89 01 b8 ff ff ff ff eb bf 0f 1f 44 00 00 b8 50 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e9 92 0d 00 f7 d8 64 89 \n---truncated---","publishedAt":"2024-12-27T13:49:22.085Z","updatedAt":"2026-10-30T12:20:08.639Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"c8bf625e188593232d515fb50e240305b6ae14dd","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"31fabf70d58388d5475e48ca8a6b7d2847b36678","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"1d76332d783db12684b67592f1fb2057b88af4c3","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"73a57b25b4df23f22814fc06b7e8f9cf570be026","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"7afb86733685c64c604d32faf00fa4a1f22c2ab1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/cached_dir.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.64","status":"unaffected","lessThanOrEqual":"6.6.*","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/smb/client/cached_dir.c"]}],"references":["https://git.kernel.org/stable/c/c8bf625e188593232d515fb50e240305b6ae14dd","https://git.kernel.org/stable/c/31fabf70d58388d5475e48ca8a6b7d2847b36678","https://git.kernel.org/stable/c/1d76332d783db12684b67592f1fb2057b88af4c3","https://git.kernel.org/stable/c/73a57b25b4df23f22814fc06b7e8f9cf570be026","https://git.kernel.org/stable/c/7afb86733685c64c604d32faf00fa4a1f22c2ab1"],"weaknesses":["CWE-401"],"ingestedAt":"2026-10-30T12:36:04.432Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2024/53xxx/CVE-2024-53178.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-53178","state":"PUBLISHED","datePublished":"2024-12-27T13:49:22.085Z","dateUpdated":"2026-10-30T12:20:08.639Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-11-19T17:17:25.008Z"},"containers":{"cna":{"title":"smb: Don't leak cfid when reconnect races with open_cached_dir","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: Don't leak cfid when reconnect races with open_cached_dir\n\nopen_cached_dir() may either race with the tcon reconnection even before\ncompound_send_recv() or directly trigger a reconnection via\nSMB2_open_init() or SMB_query_info_init().\n\nThe reconnection process invokes invalidate_all_cached_dirs() via\ncifs_mark_open_files_invalid(), which removes all cfids from the\ncfids->entries list but doesn't drop a ref if has_lease isn't true. This\nresults in the currently-being-constructed cfid not being on the list,\nbut still having a refcount of 2. It leaks if returned from\nopen_cached_dir().\n\nFix this by setting cfid->has_lease when the ref is actually taken; the\ncfid will not be used by other threads until it has a valid time.\n\nAddresses these kmemleaks:\n\nunreferenced object 0xffff8881090c4000 (size 1024):\n  comm \"bash\", pid 1860, jiffies 4295126592\n  hex dump (first 32 bytes):\n    00 01 00 00 00 00 ad de 22 01 00 00 00 00 ad de  ........\".......\n    00 ca 45 22 81 88 ff ff f8 dc 4f 04 81 88 ff ff  ..E\"......O.....\n  backtrace (crc 6f58c20f):\n    [<ffffffff8b895a1e>] __kmalloc_cache_noprof+0x2be/0x350\n    [<ffffffff8bda06e3>] open_cached_dir+0x993/0x1fb0\n    [<ffffffff8bdaa750>] cifs_readdir+0x15a0/0x1d50\n    [<ffffffff8b9a853f>] iterate_dir+0x28f/0x4b0\n    [<ffffffff8b9a9aed>] __x64_sys_getdents64+0xfd/0x200\n    [<ffffffff8cf6da05>] do_syscall_64+0x95/0x1a0\n    [<ffffffff8d00012f>] entry_SYSCALL_64_after_hwframe+0x76/0x7e\nunreferenced object 0xffff8881044fdcf8 (size 8):\n  comm \"bash\", pid 1860, jiffies 4295126592\n  hex dump (first 8 bytes):\n    00 cc cc cc cc cc cc cc                          ........\n  backtrace (crc 10c106a9):\n    [<ffffffff8b89a3d3>] __kmalloc_node_track_caller_noprof+0x363/0x480\n    [<ffffffff8b7d7256>] kstrdup+0x36/0x60\n    [<ffffffff8bda0700>] open_cached_dir+0x9b0/0x1fb0\n    [<ffffffff8bdaa750>] cifs_readdir+0x15a0/0x1d50\n    [<ffffffff8b9a853f>] iterate_dir+0x28f/0x4b0\n    [<ffffffff8b9a9aed>] __x64_sys_getdents64+0xfd/0x200\n    [<ffffffff8cf6da05>] do_syscall_64+0x95/0x1a0\n    [<ffffffff8d00012f>] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nAnd addresses these BUG splats when unmounting the SMB filesystem:\n\nBUG: Dentry ffff888140590ba0{i=1000000000080,n=/}  still in use (2) [unmount of cifs cifs]\nWARNING: CPU: 3 PID: 3433 at fs/dcache.c:1536 umount_check+0xd0/0x100\nModules linked in:\nCPU: 3 UID: 0 PID: 3433 Comm: bash Not tainted 6.12.0-rc4-g850925a8133c-dirty #49\nHardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020\nRIP: 0010:umount_check+0xd0/0x100\nCode: 8d 7c 24 40 e8 31 5a f4 ff 49 8b 54 24 40 41 56 49 89 e9 45 89 e8 48 89 d9 41 57 48 89 de 48 c7 c7 80 e7 db ac e8 f0 72 9a ff <0f> 0b 58 31 c0 5a 5b 5d 41 5c 41 5d 41 5e 41 5f e9 2b e5 5d 01 41\nRSP: 0018:ffff88811cc27978 EFLAGS: 00010286\nRAX: 0000000000000000 RBX: ffff888140590ba0 RCX: ffffffffaaf20bae\nRDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff8881f6fb6f40\nRBP: ffff8881462ec000 R08: 0000000000000001 R09: ffffed1023984ee3\nR10: ffff88811cc2771f R11: 00000000016cfcc0 R12: ffff888134383e08\nR13: 0000000000000002 R14: ffff8881462ec668 R15: ffffffffaceab4c0\nFS:  00007f23bfa98740(0000) GS:ffff8881f6f80000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000556de4a6f808 CR3: 0000000123c80000 CR4: 0000000000350ef0\nCall Trace:\n <TASK>\n d_walk+0x6a/0x530\n shrink_dcache_for_umount+0x6a/0x200\n generic_shutdown_super+0x52/0x2a0\n kill_anon_super+0x22/0x40\n cifs_kill_sb+0x159/0x1e0\n deactivate_locked_super+0x66/0xe0\n cleanup_mnt+0x140/0x210\n task_work_run+0xfb/0x170\n syscall_exit_to_user_mode+0x29f/0x2b0\n do_syscall_64+0xa1/0x1a0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\nRIP: 0033:0x7f23bfb93ae7\nCode: ff ff ff ff c3 66 0f 1f 44 00 00 48 8b 0d 11 93 0d 00 f7 d8 64 89 01 b8 ff ff ff ff eb bf 0f 1f 44 00 00 b8 50 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e9 92 0d 00 f7 d8 64 89 \n---truncated---"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"c8bf625e188593232d515fb50e240305b6ae14dd","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"31fabf70d58388d5475e48ca8a6b7d2847b36678","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"1d76332d783db12684b67592f1fb2057b88af4c3","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"73a57b25b4df23f22814fc06b7e8f9cf570be026","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"7afb86733685c64c604d32faf00fa4a1f22c2ab1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/cached_dir.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.64","status":"unaffected","lessThanOrEqual":"6.6.*","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/smb/client/cached_dir.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c8bf625e188593232d515fb50e240305b6ae14dd"},{"url":"https://git.kernel.org/stable/c/31fabf70d58388d5475e48ca8a6b7d2847b36678"},{"url":"https://git.kernel.org/stable/c/1d76332d783db12684b67592f1fb2057b88af4c3"},{"url":"https://git.kernel.org/stable/c/73a57b25b4df23f22814fc06b7e8f9cf570be026"},{"url":"https://git.kernel.org/stable/c/7afb86733685c64c604d32faf00fa4a1f22c2ab1"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The SMB client's cached-dir code reacts directly to remote peer behaviour — a malicious or compromised SMB server, or an on-path attacker able to drop/reset the tcp/445 connection, sets `tcon->need_reconnect` (via `cifs_reconnect()` or a `STATUS_NETWORK_NAME_DELETED` response) and thereby drives `invalidate_all_cached_dirs()` into the window that leaks the cfid.\nAC:L - The attacker controls the reconnect side and can force it repeatedly; moreover `open_cached_dir()` triggers the reconnect synchronously inside `SMB2_open_init()` once `need_reconnect` is set, so the leak is deterministic rather than a race that must be won, and each leak pins another dentry/inode.\nPR:N - No credentials or privileges on the target client are needed — the attack originates from the server/network side, and the client-side trigger is an ordinary unprivileged `getdents64()`/`stat` on the mount performed by any process or background daemon.\nUI:N - Against an already-mounted share (fstab/autofs/automounted corporate file server) no victim action is required; routine directory access by any existing process supplies the `open_cached_dir()` call while the attacker forces reconnection.\nS:U - The leaked refcount, exhausted memory and resulting BUG are all confined to the kernel of the affected client; no security boundary such as a VM or IOMMU domain is crossed.\nC:N - The defect is an over-reference/leak, not an under-reference or out-of-bounds access; no freed or out-of-bounds memory is read and no kernel data is disclosed to the attacker.\nI:N - Nothing is written out of bounds and no freed object is reused, so the bug provides no mechanism to modify kernel or user data.\nA:H - Each triggered leak permanently loses a `cached_fid`, its path string and a pinned dentry/inode, so repeated triggering exhausts memory, and unmounting the share hits `umount_check` WARN plus `VFS: Busy inodes after unmount` → `BUG()` at fs/super.c:661 (or `VFS_PTR_POISON`ed inodes that crash on later use) — a hard kernel crash."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:20:08.639Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.6.64"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.11.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.12.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.13"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":4.7,"attackVector":"LOCAL","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"HIGH","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"id":"CVE-2024-53178","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2025-10-01T20:04:23.545545Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-401","lang":"en","type":"CWE","description":"CWE-401 Missing Release of Memory after Effective Lifetime"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-10-01T20:07:21.785Z"}}]}}}