Use-after-free in Linux kernel - CVE-2026-31718
Published: May 2, 2026
Vulnerability identifier: #VU128985
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-31718
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to a use-after-free in __ksmbd_close_fd() when processing durable file handles that survive session disconnect and are later timed out by the durable scavenger. A remote user can trigger session disconnect without SMB2_LOGOFF and cause lock cleanup to access a freed connection object to cause a denial of service.
The issue occurs when a durable file handle is preserved for later reconnection and byte-range locks remain associated with the old connection.
How to mitigate CVE-2026-31718
Install security update from vendor's repository.