Expired pointer dereference in Linux kernel - CVE-2026-89676
Published: September 12, 2026
Vulnerability identifier: #VU149126
CSH Severity: Medium
CVSS v4: 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]
CVE-ID: CVE-2026-89676
CWE-ID: CWE-825
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to an expired pointer dereference in the nfsd asynchronous COPY stateid IDR handling when processing asynchronous NFS COPY requests. A remote attacker can submit an asynchronous COPY request to cause a denial of service.
Exploitation requires an IDR walker to dereference reused request memory whose contents resemble an expired NFS4_COPYNOTIFY_STID.
Affected software
Linux kernel
How to mitigate CVE-2026-89676
Install security update from vendor's repository.