SB20260625157 - Improper update of reference count in Linux kernel nfsd

Description

This security bulletin contains information about 1 vulnerability.

1) Improper update of reference count (CVE-ID: CVE-2026-53026)

CWE-ID: CWE-911 - Improper Update of Reference Count

CVSSv4: 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

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to improper reference count management in nfsd4_add_rdaccess_to_wrdeleg when handling concurrent NFS file access state updates. A remote user can trigger concurrent access patterns to cause a denial of service.

The issue can leave nfsd_file objects unreleased and trigger a BUG in kmem_cache_destroy() when the nfs-server service is stopped.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/4584229395d0d65bd517780afe97ffea07cb2c3d
• https://git.kernel.org/stable/c/b48f44f36e6607b2f818560f19deb86b4a9c717b
• https://git.kernel.org/stable/c/b81572b073441dfd32213e41857676d0dbff4665