Riskcovery

CVE-2025-40320

smb: client: fix potential cfid UAF in smb2_query_info_compound

State
Published
Severity
9.8 Critical
Published
Dec 8, 2025
Updated
Oct 15, 2026
Reserved
Apr 16, 2025

Read the record on cve.org

Description

In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix potential cfid UAF in smb2_query_info_compound

When smb2_query_info_compound() retries, a previously allocated cfid may have been freed in the first attempt. Because cfid wasn't reset on replay, later cleanup could act on a stale pointer, leading to a potential use-after-free.

Reinitialize cfid to NULL under the replay label.

Example trace (trimmed):

refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 11224 at ../lib/refcount.c:28 refcount_warn_saturate+0x9c/0x110 [...] RIP: 0010:refcount_warn_saturate+0x9c/0x110 [...] Call Trace: <TASK> smb2_query_info_compound+0x29c/0x5c0 [cifs f90b72658819bd21c94769b6a652029a07a7172f] ? step_into+0x10d/0x690 ? __legitimize_path+0x28/0x60 smb2_queryfs+0x6a/0xf0 [cifs f90b72658819bd21c94769b6a652029a07a7172f] smb311_queryfs+0x12d/0x140 [cifs f90b72658819bd21c94769b6a652029a07a7172f] ? kmem_cache_alloc+0x18a/0x340 ? getname_flags+0x46/0x1e0 cifs_statfs+0x9f/0x2b0 [cifs f90b72658819bd21c94769b6a652029a07a7172f] statfs_by_dentry+0x67/0x90 vfs_statfs+0x16/0xd0 user_statfs+0x54/0xa0 __do_sys_statfs+0x20/0x50 do_syscall_64+0x58/0x80

Scores

CVSSScoreVectorSource
3.19.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HLinux

Weaknesses

The record names no weakness.

Affected Products

ProductVersions
LinuxLinux
  • 433042a91f9373241307725b52de573933ffedbf to before 939c4e33005e2a56ea8fcedddf0da92df864bd3bAffected
  • 4f1fffa2376922f3d1d506e49c0fd445b023a28e to before 327f89c21601ebb7889f8c97754b76f08ce95a0cAffected
  • 4f1fffa2376922f3d1d506e49c0fd445b023a28e to before b556c278d43f4707a9073ca74d55581b4f279806Affected
  • 4f1fffa2376922f3d1d506e49c0fd445b023a28e to before 5c76f9961c170552c1d07c830b5e145475151600Affected
  • 6.6.32 to before 6.6.117Affected
LinuxLinux
  • 6.8Affected
  • before 6.8Not affected
  • 6.6.117 through 6.6.*Not affected
  • 6.12.58 through 6.12.*Not affected
  • 6.17.8 through 6.17.*Not affected
  • 6.18 and laterNot affected

References

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