PT-2025-49449 · Linux+3 · Linux Kernel+3

CVE-2025-40320

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Published

2025-10-27

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Updated

2026-08-30

CVSS v3.1

9.8

Critical

VectorAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)
Description The Linux kernel contains a flaw within the Server Message Block (SMB) client implementation, specifically in the smb2 query info compound function. A use-after-free condition can occur when the function retries an operation, potentially acting on a stale pointer if a previously allocated context ID (cfid) has been freed during the first attempt. This can lead to system instability. The issue is triggered when cfid is not reset to NULL upon replay. A trace indicates a refcount underflow and use-after-free occurring at refcount warn saturate.
Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

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Weakness Enumeration

Related Identifiers

ALSA-2026:18134
BDU:2026-02963
CVE-2025-40320
MGASA-2026-0017
MGASA-2026-0018
OESA-2026-1303
OESA-2026-1304
OESA-2026-1305
OPENSUSE-SU-2026:20145-1
RHSA-2026:18134
SUSE-SU-2026:0278-1
SUSE-SU-2026:0281-1
SUSE-SU-2026:0293-1
SUSE-SU-2026:0315-1
SUSE-SU-2026:20207-1
SUSE-SU-2026:20220-1
SUSE-SU-2026:20228-1
SUSE-SU-2026:20477-1
SUSE-SU-2026:20498-1
SUSE-SU-2026:20564-1
SUSE-SU-2026:20845-1
SUSE-SU-2026:20876-1
USN-8029-1
USN-8029-2
USN-8029-3
USN-8030-1
USN-8048-1
USN-8095-1
USN-8095-2
USN-8095-3
USN-8095-4
USN-8095-5
USN-8100-1
USN-8125-1
USN-8126-1
USN-8165-1
USN-8261-1

Affected Products

Debian
Linuxmint
Linux Kernel
Ubuntu