Use-after-free in Linux kernel - CVE-2026-89712
Published: September 12, 2026
Vulnerability identifier: #VU149095
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-2026-89712
CWE-ID: CWE-416
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 a use-after-free in nfsd4_ssc_expire_umount() when processing concurrent NFS server operations while an expired inter-server source mount is being unmounted. A remote attacker can trigger concurrent operations that cause the expiration walk to dereference a freed nfsd4_ssc_umount_item to cause a denial of service.
Affected software
Linux kernel
How to mitigate CVE-2026-89712
Install security update from vendor's repository.