SB20260912120 - Use-after-free in Linux kernel nfsd
Published: September 12, 2026
Security Bulletin ID
SB20260912120
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Partial DoS
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use-after-free (CVE-ID: CVE-2026-89661)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a local privileged user to cause a denial of service.
The vulnerability exists due to a use-after-free in nfsd4_cancel_copy_by_sb() when processing a filesystem path written to /proc/fs/nfsd/unlock_filesystem after NFS server shutdown. A local privileged user can stop the NFS server and write a filesystem path to the endpoint to cause a denial of service.
Remediation
Install update from vendor's website.