{"id":"CVE-2023-52751","state":"PUBLISHED","title":"smb: client: fix use-after-free in smb2_query_info_compound()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-after-free in smb2_query_info_compound()\n\nThe following UAF was triggered when running fstests generic/072 with\nKASAN enabled against Windows Server 2022 and mount options\n'multichannel,max_channels=2,vers=3.1.1,mfsymlinks,noperm'\n\n  BUG: KASAN: slab-use-after-free in smb2_query_info_compound+0x423/0x6d0 [cifs]\n  Read of size 8 at addr ffff888014941048 by task xfs_io/27534\n\n  CPU: 0 PID: 27534 Comm: xfs_io Not tainted 6.6.0-rc7 #1\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS\n  rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014\n  Call Trace:\n   dump_stack_lvl+0x4a/0x80\n   print_report+0xcf/0x650\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? __phys_addr+0x46/0x90\n   kasan_report+0xda/0x110\n   ? smb2_query_info_compound+0x423/0x6d0 [cifs]\n   ? smb2_query_info_compound+0x423/0x6d0 [cifs]\n   smb2_query_info_compound+0x423/0x6d0 [cifs]\n   ? __pfx_smb2_query_info_compound+0x10/0x10 [cifs]\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? __stack_depot_save+0x39/0x480\n   ? kasan_save_stack+0x33/0x60\n   ? kasan_set_track+0x25/0x30\n   ? ____kasan_slab_free+0x126/0x170\n   smb2_queryfs+0xc2/0x2c0 [cifs]\n   ? __pfx_smb2_queryfs+0x10/0x10 [cifs]\n   ? __pfx___lock_acquire+0x10/0x10\n   smb311_queryfs+0x210/0x220 [cifs]\n   ? __pfx_smb311_queryfs+0x10/0x10 [cifs]\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? __lock_acquire+0x480/0x26c0\n   ? lock_release+0x1ed/0x640\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? do_raw_spin_unlock+0x9b/0x100\n   cifs_statfs+0x18c/0x4b0 [cifs]\n   statfs_by_dentry+0x9b/0xf0\n   fd_statfs+0x4e/0xb0\n   __do_sys_fstatfs+0x7f/0xe0\n   ? __pfx___do_sys_fstatfs+0x10/0x10\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? lockdep_hardirqs_on_prepare+0x136/0x200\n   ? srso_alias_return_thunk+0x5/0x7f\n   do_syscall_64+0x3f/0x90\n   entry_SYSCALL_64_after_hwframe+0x6e/0xd8\n\n  Allocated by task 27534:\n   kasan_save_stack+0x33/0x60\n   kasan_set_track+0x25/0x30\n   __kasan_kmalloc+0x8f/0xa0\n   open_cached_dir+0x71b/0x1240 [cifs]\n   smb2_query_info_compound+0x5c3/0x6d0 [cifs]\n   smb2_queryfs+0xc2/0x2c0 [cifs]\n   smb311_queryfs+0x210/0x220 [cifs]\n   cifs_statfs+0x18c/0x4b0 [cifs]\n   statfs_by_dentry+0x9b/0xf0\n   fd_statfs+0x4e/0xb0\n   __do_sys_fstatfs+0x7f/0xe0\n   do_syscall_64+0x3f/0x90\n   entry_SYSCALL_64_after_hwframe+0x6e/0xd8\n\n  Freed by task 27534:\n   kasan_save_stack+0x33/0x60\n   kasan_set_track+0x25/0x30\n   kasan_save_free_info+0x2b/0x50\n   ____kasan_slab_free+0x126/0x170\n   slab_free_freelist_hook+0xd0/0x1e0\n   __kmem_cache_free+0x9d/0x1b0\n   open_cached_dir+0xff5/0x1240 [cifs]\n   smb2_query_info_compound+0x5c3/0x6d0 [cifs]\n   smb2_queryfs+0xc2/0x2c0 [cifs]\n\nThis is a race between open_cached_dir() and cached_dir_lease_break()\nwhere the cache entry for the open directory handle receives a lease\nbreak while creating it.  And before returning from open_cached_dir(),\nwe put the last reference of the new @cfid because of\n!@cfid->has_lease.\n\nBesides the UAF, while running xfstests a lot of missed lease breaks\nhave been noticed in tests that run several concurrent statfs(2) calls\non those cached fids\n\n  CIFS: VFS: \\\\w22-root1.gandalf.test No task to wake, unknown frame...\n  CIFS: VFS: \\\\w22-root1.gandalf.test Cmd: 18 Err: 0x0 Flags: 0x1...\n  CIFS: VFS: \\\\w22-root1.gandalf.test smb buf 00000000715bfe83 len 108\n  CIFS: VFS: Dump pending requests:\n  CIFS: VFS: \\\\w22-root1.gandalf.test No task to wake, unknown frame...\n  CIFS: VFS: \\\\w22-root1.gandalf.test Cmd: 18 Err: 0x0 Flags: 0x1...\n  CIFS: VFS: \\\\w22-root1.gandalf.test smb buf 000000005aa7316e len 108\n  ...\n\nTo fix both, in open_cached_dir() ensure that @cfid->has_lease is set\nright before sending out compounded request so that any potential\nlease break will be get processed by demultiplex thread while we're\nstill caching @cfid.  And, if open failed for some reason, re-check\n@cfid->has_lease to decide whether or not put lease reference.","publishedAt":"2024-05-21T15:30:40.226Z","updatedAt":"2026-10-30T12:17:20.902Z","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":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"06c106e1e8568e840c946cc0222579e3d29dab8e","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"6db94d08359c43f2c8fe372811cdee04564a41b9","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"93877b9afc2994c89362007aac480a7b150f386f","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"5c86919455c1edec99ebd3338ad213b59271a71b","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":"6.5.13","status":"unaffected","lessThanOrEqual":"6.5.*","versionType":"semver"},{"version":"6.6.3","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.7","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/06c106e1e8568e840c946cc0222579e3d29dab8e","https://git.kernel.org/stable/c/6db94d08359c43f2c8fe372811cdee04564a41b9","https://git.kernel.org/stable/c/93877b9afc2994c89362007aac480a7b150f386f","https://git.kernel.org/stable/c/5c86919455c1edec99ebd3338ad213b59271a71b"],"weaknesses":[],"ingestedAt":"2026-10-30T12:34:06.950Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/52xxx/CVE-2023-52751.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-52751","state":"PUBLISHED","datePublished":"2024-05-21T15:30:40.226Z","dateUpdated":"2026-10-30T12:17:20.902Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-05-21T15:19:24.234Z"},"containers":{"cna":{"title":"smb: client: fix use-after-free in smb2_query_info_compound()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-after-free in smb2_query_info_compound()\n\nThe following UAF was triggered when running fstests generic/072 with\nKASAN enabled against Windows Server 2022 and mount options\n'multichannel,max_channels=2,vers=3.1.1,mfsymlinks,noperm'\n\n  BUG: KASAN: slab-use-after-free in smb2_query_info_compound+0x423/0x6d0 [cifs]\n  Read of size 8 at addr ffff888014941048 by task xfs_io/27534\n\n  CPU: 0 PID: 27534 Comm: xfs_io Not tainted 6.6.0-rc7 #1\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS\n  rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014\n  Call Trace:\n   dump_stack_lvl+0x4a/0x80\n   print_report+0xcf/0x650\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? __phys_addr+0x46/0x90\n   kasan_report+0xda/0x110\n   ? smb2_query_info_compound+0x423/0x6d0 [cifs]\n   ? smb2_query_info_compound+0x423/0x6d0 [cifs]\n   smb2_query_info_compound+0x423/0x6d0 [cifs]\n   ? __pfx_smb2_query_info_compound+0x10/0x10 [cifs]\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? __stack_depot_save+0x39/0x480\n   ? kasan_save_stack+0x33/0x60\n   ? kasan_set_track+0x25/0x30\n   ? ____kasan_slab_free+0x126/0x170\n   smb2_queryfs+0xc2/0x2c0 [cifs]\n   ? __pfx_smb2_queryfs+0x10/0x10 [cifs]\n   ? __pfx___lock_acquire+0x10/0x10\n   smb311_queryfs+0x210/0x220 [cifs]\n   ? __pfx_smb311_queryfs+0x10/0x10 [cifs]\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? __lock_acquire+0x480/0x26c0\n   ? lock_release+0x1ed/0x640\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? do_raw_spin_unlock+0x9b/0x100\n   cifs_statfs+0x18c/0x4b0 [cifs]\n   statfs_by_dentry+0x9b/0xf0\n   fd_statfs+0x4e/0xb0\n   __do_sys_fstatfs+0x7f/0xe0\n   ? __pfx___do_sys_fstatfs+0x10/0x10\n   ? srso_alias_return_thunk+0x5/0x7f\n   ? lockdep_hardirqs_on_prepare+0x136/0x200\n   ? srso_alias_return_thunk+0x5/0x7f\n   do_syscall_64+0x3f/0x90\n   entry_SYSCALL_64_after_hwframe+0x6e/0xd8\n\n  Allocated by task 27534:\n   kasan_save_stack+0x33/0x60\n   kasan_set_track+0x25/0x30\n   __kasan_kmalloc+0x8f/0xa0\n   open_cached_dir+0x71b/0x1240 [cifs]\n   smb2_query_info_compound+0x5c3/0x6d0 [cifs]\n   smb2_queryfs+0xc2/0x2c0 [cifs]\n   smb311_queryfs+0x210/0x220 [cifs]\n   cifs_statfs+0x18c/0x4b0 [cifs]\n   statfs_by_dentry+0x9b/0xf0\n   fd_statfs+0x4e/0xb0\n   __do_sys_fstatfs+0x7f/0xe0\n   do_syscall_64+0x3f/0x90\n   entry_SYSCALL_64_after_hwframe+0x6e/0xd8\n\n  Freed by task 27534:\n   kasan_save_stack+0x33/0x60\n   kasan_set_track+0x25/0x30\n   kasan_save_free_info+0x2b/0x50\n   ____kasan_slab_free+0x126/0x170\n   slab_free_freelist_hook+0xd0/0x1e0\n   __kmem_cache_free+0x9d/0x1b0\n   open_cached_dir+0xff5/0x1240 [cifs]\n   smb2_query_info_compound+0x5c3/0x6d0 [cifs]\n   smb2_queryfs+0xc2/0x2c0 [cifs]\n\nThis is a race between open_cached_dir() and cached_dir_lease_break()\nwhere the cache entry for the open directory handle receives a lease\nbreak while creating it.  And before returning from open_cached_dir(),\nwe put the last reference of the new @cfid because of\n!@cfid->has_lease.\n\nBesides the UAF, while running xfstests a lot of missed lease breaks\nhave been noticed in tests that run several concurrent statfs(2) calls\non those cached fids\n\n  CIFS: VFS: \\\\w22-root1.gandalf.test No task to wake, unknown frame...\n  CIFS: VFS: \\\\w22-root1.gandalf.test Cmd: 18 Err: 0x0 Flags: 0x1...\n  CIFS: VFS: \\\\w22-root1.gandalf.test smb buf 00000000715bfe83 len 108\n  CIFS: VFS: Dump pending requests:\n  CIFS: VFS: \\\\w22-root1.gandalf.test No task to wake, unknown frame...\n  CIFS: VFS: \\\\w22-root1.gandalf.test Cmd: 18 Err: 0x0 Flags: 0x1...\n  CIFS: VFS: \\\\w22-root1.gandalf.test smb buf 000000005aa7316e len 108\n  ...\n\nTo fix both, in open_cached_dir() ensure that @cfid->has_lease is set\nright before sending out compounded request so that any potential\nlease break will be get processed by demultiplex thread while we're\nstill caching @cfid.  And, if open failed for some reason, re-check\n@cfid->has_lease to decide whether or not put lease reference."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"06c106e1e8568e840c946cc0222579e3d29dab8e","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"6db94d08359c43f2c8fe372811cdee04564a41b9","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"93877b9afc2994c89362007aac480a7b150f386f","versionType":"git"},{"version":"ebe98f1447bbccf8228335c62d86af02a0ed23f7","status":"affected","lessThan":"5c86919455c1edec99ebd3338ad213b59271a71b","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":"6.5.13","status":"unaffected","lessThanOrEqual":"6.5.*","versionType":"semver"},{"version":"6.6.3","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.7","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/06c106e1e8568e840c946cc0222579e3d29dab8e"},{"url":"https://git.kernel.org/stable/c/6db94d08359c43f2c8fe372811cdee04564a41b9"},{"url":"https://git.kernel.org/stable/c/93877b9afc2994c89362007aac480a7b150f386f"},{"url":"https://git.kernel.org/stable/c/5c86919455c1edec99ebd3338ad213b59271a71b"}],"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 - Vulnerable code is in fs/smb/client/ and is reached via local VFS syscalls (fstatfs→cifs_statfs→smb2_queryfs→smb2_query_info_compound→open_cach ed_dir, also readdir/inode paths), not by an in-kernel SMB server accepting remote connections.\nAC:L - The attacker can drive both sides of the race—hammering concurrent statfs/readdir on the mount while forcing directory lease breaks via a second SMB client (or a malicious server sending breaks right after the lease grant)—so success does not depend on uncontrollable conditions.\nPR:L - Any unprivileged local user who can access an already-mounted CIFS/SMB3 share can invoke fstatfs/getdents on that path; no CAP_SYS_ADMIN or other elevated capability is required on the vulnerable path.\nUI:N - The attacker triggers the UAF solely through their own syscalls on a reachable mount; no separate victim action (such as opening a crafted file) is required in the worst reasonable deployment with a pre-mounted share.\nS:U - This is a standard in-kernel slab UAF enabling local privilege escalation within the same host kernel authority and does not cross a VM, IOMMU, or other security boundary.\nC:H - Use-after-free of the cached_fid heap object lets an attacker reclaim and control the freed slab contents, enabling arbitrary kernel memory disclosure primitives.\nI:H - The same UAF is exploitable via heap spraying into write/control-flow hijack primitives against kernel objects, enabling integrity compromise and code execution.\nA:H - The UAF causes a kernel oops/crash when the freed cached_fid is dereferenced (as shown by the KASAN slab-use-after-free report), fully denying availability even without further exploitation."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:17:20.902Z"},"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":"6.5.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.6.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.7"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/6db94d08359c43f2c8fe372811cdee04564a41b9","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/93877b9afc2994c89362007aac480a7b150f386f","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/5c86919455c1edec99ebd3338ad213b59271a71b","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-02T23:11:36.015Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2023-52751","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-09-10T15:37:15.794672Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-09-11T17:33:32.822Z"}}]}}}