SB2026091963 - Use-after-free in Linux kernel smb server
Published: September 19, 2026
Security Bulletin ID
SB2026091963
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-2026-90156)
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 the ksmbd smb2_lock function when processing deferred SMB lock requests during asynchronous setup failures. A remote attacker can send SMB lock requests that result in deferred locks to cause a denial of service.
Remediation
Install update from vendor's website.