SB2026091962 - Use-after-free in Linux kernel smb server
Published: September 19, 2026
Security Bulletin ID
SB2026091962
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use-after-free (CVE-ID: CVE-2026-90155)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to use-after-free in ksmbd byte-range lock handling when processing SMB byte-range lock requests with blocked dependent waiters. A remote attacker can submit lock requests that leave a dependent waiter attached to a freed lock to cause a denial of service.
Remediation
Install update from vendor's website.