Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-89917
Published: September 17, 2026
Vulnerability identifier: #VU150374
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89917
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a time-of-check to time-of-use race condition in the Arm64 KVM nested virtualization VNCR mapping logic when concurrent VNCR TLB invalidation and vcpu_put() unmapping occur. A local user can trigger the concurrent operations to cause a denial of service.
Affected software
Linux kernel
How to mitigate CVE-2026-89917
Install security update from vendor's repository.