NULL pointer dereference in Linux kernel - CVE-2026-64140
Published: July 20, 2026
Vulnerability identifier: #VU138504
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-2026-64140
CWE-ID: CWE-476
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 null pointer dereference in proc_show_files() when reading /proc/fs/ksmbd/files after an SMB2 client opens a file with a durable v2 handle and issues SMB2 SESSION_LOGOFF. A remote user can establish an SMB2 session and trigger the vulnerable state to cause a denial of service.
Exploitation requires a share configured with durable handles enabled, and the crash occurs during the interval before the durable scavenger removes the disconnected file pointer.
How to mitigate CVE-2026-64140
Install security update from vendor's repository.