SB2026061071 - Race condition in Linux kernel x86 kvm

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-46295)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a race condition in __kvm_apic_update_irr and KVM x86 LAPIC interrupt handling when synchronizing posted interrupts to the IRR in nested virtualization. A local user can trigger the race during nested VM interrupt delivery to cause a denial of service.

The issue causes a spurious kernel WARNING and a wasted L2 VM-Enter/VM-Exit cycle, while the pending interrupt is not lost.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/33fd0ccd2590b470b65adcca288615ad3b5e3e06
• https://git.kernel.org/stable/c/4b6b06a8b12bfd95f9015074b1430c1480908073
• https://git.kernel.org/stable/c/bb1703949dcaa9a49c338dee075f659f4634214d