Review reviewCritical

CVE-2025-40320

Linux

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_satur...

CVSS: 9.8
EPSS: 0.41%
CISA KEV: Not listed
Published: 2025.12.08

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.41%

Technical severityCVSS 9.8

Vulnerability overview

Affected product and versions

Product: Linux
Affected versions: >= 433042a91f9373241307725b52de573933ffedbf < 939c4e33005e2a56ea8fcedddf0da92df864bd3b, >= 4f1fffa2376922f3d1d506e49c0fd445b023a28e < 327f89c21601ebb7889f8c97754b76f08ce95a0c, >= 4f1fffa2376922f3d1d506e49c0fd445b023a28e < b556c278d43f4707a9073ca74d55581b4f279806, >= 4f1fffa2376922f3d1d506e49c0fd445b023a28e < 5c76f9961c170552c1d07c830b5e145475151600, >= 6.6.32 < 6.6.117, >= 6.8
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Linux and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE: Not available