SB2026091752 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel arm64 kvm
Published: September 17, 2026
Security Bulletin ID
SB2026091752
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-89917)
CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition
CVSSv4: 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]
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.
Remediation
Install update from vendor's website.