--- id: CVE-2024-53178 title: 'smb: Don''t leak cfid when reconnect races with open_cached_dir' summary: |- In the Linux kernel, the following vulnerability has been resolved: smb: Don't leak cfid when reconnect races with open_cached_dir open_cached_dir() may either race with the tcon reconnection even before compound_send_recv() or directl… severity: high cvss: 7.5 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H' cvssSource: cna vendor: Linux product: Linux affected: - >- Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < c8bf625e188593232d515fb50e240305b6ae14dd - >- Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < 31fabf70d58388d5475e48ca8a6b7d2847b36678 - >- Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < 1d76332d783db12684b67592f1fb2057b88af4c3 - >- Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < 73a57b25b4df23f22814fc06b7e8f9cf570be026 - >- Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < 7afb86733685c64c604d32faf00fa4a1f22c2ab1 - Linux 6.1 ssvc: exploitation: none automatable: 'no' technicalImpact: partial timestamp: '2025-10-01T20:04:23.545545Z' published: '2024-12-27' updated: '2026-10-30' sourceUpdated: '2026-10-30T12:20:08.639Z' source: CVEORG sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2024-53178' 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' tags: - cve.org epss: 0.00544 epssPercentile: 0.45953 ingestedAt: '2026-11-03T14:47:02.517Z' --- ## Overview In the Linux kernel, the following vulnerability has been resolved: smb: Don't leak cfid when reconnect races with open_cached_dir open_cached_dir() may either race with the tcon reconnection even before compound_send_recv() or directly trigger a reconnection via SMB2_open_init() or SMB_query_info_init(). The reconnection process invokes invalidate_all_cached_dirs() via cifs_mark_open_files_invalid(), which removes all cfids from the cfids->entries list but doesn't drop a ref if has_lease isn't true. This results in the currently-being-constructed cfid not being on the list, but still having a refcount of 2. It leaks if returned from open_cached_dir(). Fix this by setting cfid->has_lease when the ref is actually taken; the cfid will not be used by other threads until it has a valid time. Addresses these kmemleaks: unreferenced object 0xffff8881090c4000 (size 1024): comm "bash", pid 1860, jiffies 4295126592 hex dump (first 32 bytes): 00 01 00 00 00 00 ad de 22 01 00 00 00 00 ad de ........"....... 00 ca 45 22 81 88 ff ff f8 dc 4f 04 81 88 ff ff ..E"......O..... backtrace (crc 6f58c20f): [] __kmalloc_cache_noprof+0x2be/0x350 [] open_cached_dir+0x993/0x1fb0 [] cifs_readdir+0x15a0/0x1d50 [] iterate_dir+0x28f/0x4b0 [] __x64_sys_getdents64+0xfd/0x200 [] do_syscall_64+0x95/0x1a0 [] entry_SYSCALL_64_after_hwframe+0x76/0x7e unreferenced object 0xffff8881044fdcf8 (size 8): comm "bash", pid 1860, jiffies 4295126592 hex dump (first 8 bytes): 00 cc cc cc cc cc cc cc ........ backtrace (crc 10c106a9): [] __kmalloc_node_track_caller_noprof+0x363/0x480 [] kstrdup+0x36/0x60 [] open_cached_dir+0x9b0/0x1fb0 [] cifs_readdir+0x15a0/0x1d50 [] iterate_dir+0x28f/0x4b0 [] __x64_sys_getdents64+0xfd/0x200 [] do_syscall_64+0x95/0x1a0 [] entry_SYSCALL_64_after_hwframe+0x76/0x7e And addresses these BUG splats when unmounting the SMB filesystem: BUG: Dentry ffff888140590ba0{i=1000000000080,n=/} still in use (2) [unmount of cifs cifs] WARNING: CPU: 3 PID: 3433 at fs/dcache.c:1536 umount_check+0xd0/0x100 Modules linked in: CPU: 3 UID: 0 PID: 3433 Comm: bash Not tainted 6.12.0-rc4-g850925a8133c-dirty #49 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 RIP: 0010:umount_check+0xd0/0x100 Code: 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 RSP: 0018:ffff88811cc27978 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff888140590ba0 RCX: ffffffffaaf20bae RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff8881f6fb6f40 RBP: ffff8881462ec000 R08: 0000000000000001 R09: ffffed1023984ee3 R10: ffff88811cc2771f R11: 00000000016cfcc0 R12: ffff888134383e08 R13: 0000000000000002 R14: ffff8881462ec668 R15: ffffffffaceab4c0 FS: 00007f23bfa98740(0000) GS:ffff8881f6f80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000556de4a6f808 CR3: 0000000123c80000 CR4: 0000000000350ef0 Call Trace: d_walk+0x6a/0x530 shrink_dcache_for_umount+0x6a/0x200 generic_shutdown_super+0x52/0x2a0 kill_anon_super+0x22/0x40 cifs_kill_sb+0x159/0x1e0 deactivate_locked_super+0x66/0xe0 cleanup_mnt+0x140/0x210 task_work_run+0xfb/0x170 syscall_exit_to_user_mode+0x29f/0x2b0 do_syscall_64+0xa1/0x1a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f23bfb93ae7 Code: 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 ---truncated--- ## Affected - `Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < c8bf625e188593232d515fb50e240305b6ae14dd` - `Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < 31fabf70d58388d5475e48ca8a6b7d2847b36678` - `Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < 1d76332d783db12684b67592f1fb2057b88af4c3` - `Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < 73a57b25b4df23f22814fc06b7e8f9cf570be026` - `Linux >= ebe98f1447bbccf8228335c62d86af02a0ed23f7 < 7afb86733685c64c604d32faf00fa4a1f22c2ab1` - `Linux 6.1` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges.