Race condition in Linux kernel - CVE-2026-89686
Published: September 12, 2026
Vulnerability identifier: #VU149120
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-2026-89686
CWE-ID: CWE-362
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 race condition in nfsd4_alloc_layout_stateid when concurrently revoking a delegation and processing a LAYOUTGET request. A remote attacker can send concurrent NFS requests that trigger delegation recall and layout-state allocation to cause a denial of service.
Exploitation requires one NFS client to hold a delegation and fail to respond to its recall while another client opens the same file.
Affected software
Linux kernel
How to mitigate CVE-2026-89686
Install security update from vendor's repository.