CVE-2025-40320
A flaw in the Linux kernel's SMB client allows for a 'use-after-free' error during specific network operations. This occurs when the system tries to reuse information that has already been cleared from memory.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Users running a Linux kernel that utilizes the SMB client for network file sharing.
Real-world impact
An attacker could potentially exploit this to cause a system crash or execute unauthorized code by manipulating how the kernel handles memory during file system queries.
Why this severity
The critical score reflects that the vulnerability is easy to exploit remotely over a network without requiring user interaction or special privileges, and it can lead to a total loss of confidentiality, integrity, and availability.
What to do about it
- 01Update the Linux kernel to the version containing the fix for smb2_query_info_compound.
NVD-referenced vendor advisory
Timeline
- Dec 8, 2025 · Dec 8, 2025PublishedDisclosed and added to the National Vulnerability Database.
- Jul 30, 2026 · 6d agoAdvisory updatedThe NVD record was last revised.
- Jul 30, 2026 · 6d agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.