CVE-2025-40328

smb: client: fix potential UAF in smb2_close_cached_fid()

HIGH
8.8
CVSS Score
Published: December 9, 2025 at 04:09 AM UTC
Updated: October 15, 2026 at 10:19 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH8.8
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in smb2_close_cached_fid() find_or_create_cached_dir() could grab a new reference after kref_put() had seen the refcount drop to zero but before cfid_list_lock is acquired in smb2_close_cached_fid(), leading to use-after-free. Switch to kref_put_lock() so cfid_release() is called with cfid_list_lock held, closing that gap.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.1ebe98f1447bbccf8228335c62d86af02a0ed23f7
Vendor states this is fixed in 065bd62412271a2d734810dd50336cae88c54427 (fixed)
Vendor states this is fixed in 734e99623c5b65bf2c03e35978a0b980ebc3c2f8 (fixed)
Vendor states this is fixed in bdb596ceb4b7c3f28786a33840263728217fbcf5 (fixed)
Vendor states this is fixed in cb52d9c86d70298de0ab7c7953653898cbc0efd6 (fixed)
Vendor states this is fixed in 6.1 (unaffected)
Vendor states this is fixed in 6.12.58 (unaffected)
Vendor states this is fixed in 6.17.8 (unaffected)
Vendor states this is fixed in 6.18 (unaffected)
Vendor states this is fixed in 6.6.117 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHLinux
Vector?

Quick Info

StatusDEFERRED

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