What is CVE-2025-40320?

CVE-2025-40320 is a unscored severity Linux kernel vulnerability, affecting Linux kernel versions from 6.6.32 onward and patched in 6.6.117, 6.12.58, 6.17.8 and others. CVE-2025-40320 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-40320?

CVE-2025-40320 has a CVSS score of pending NVD analysis out of 10, rated awaiting scoring severity.

Is there a patch available for CVE-2025-40320?

Yes, CVE-2025-40320 has been patched. Fixed versions include 6.6.117, 6.12.58, 6.17.8 and others. If you are running Linux kernel 6.6.32 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-40320 actively exploited?

CVE-2025-40320 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-40320

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

Package Linux Kernel

Published 2025-12-08

Last modified 2026-04-15

Patch available

Yes

Affected versions

Linux kernel versions 6.6.32, 6.8 and later are affected. Fixed in 6.6.117, 6.12.58, 6.17.8, 6.18 and their respective stable series.

Affected from

≥ 6.6.32 ≥ 6.8

Fixed in

✓ 6.6.117 6.6.x ✓ 6.12.58 6.12.x ✓ 6.17.8 6.17.x ✓ 6.18

References

The following references provide additional information about CVE-2025-40320 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/327f89c21601ebb7889f8c97754b76f08ce95a0c
Patch
Kernel patch commit
https://git.kernel.org/stable/c/5c76f9961c170552c1d07c830b5e145475151600
Patch
Kernel patch commit
https://git.kernel.org/stable/c/939c4e33005e2a56ea8fcedddf0da92df864bd3b
Patch

4 patch commits total View all on NVD

Frequently asked questions

What is CVE-2025-40320?

CVE-2025-40320 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.6.32 onward and has been patched in 6.6.117, 6.12.58, 6.17.8 and others. CVE-2025-40320 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
Is there a patch available for CVE-2025-40320?

Yes — CVE-2025-40320 has been patched. Fixed versions include 6.6.117, 6.12.58, 6.17.8 and others. If you are running Linux kernel 6.6.32 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-40320 actively exploited?

No — CVE-2025-40320 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.