Incomplete Internal State Distinction Affecting kernel-rt-debug package, versions *


Severity

Recommended
low

Based on CentOS security rating.

Threat Intelligence

EPSS
0.02% (7th percentile)

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  • Snyk IDSNYK-CENTOS10-KERNELRTDEBUG-16468507
  • published7 May 2026
  • disclosed6 May 2026

Introduced: 6 May 2026

NewCVE-2026-43265  (opens in a new tab)
CWE-372  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel-rt-debug.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug package and not the kernel-rt-debug package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: Ignore -EBUSY when checking nested events from vcpu_block()

Ignore -EBUSY when checking nested events after exiting a blocking state while L2 is active, as exiting to userspace will generate a spurious userspace exit, usually with KVM_EXIT_UNKNOWN, and likely lead to the VM's demise. Continuing with the wakeup isn't perfect either, as something has gone sideways if a vCPU is awakened in L2 with an injected event (or worse, a nested run pending), but continuing on gives the VM a decent chance of surviving without any major side effects.

As explained in the Fixes commits, it should be impossible for a vCPU to be put into a blocking state with an already-injected event (exception, IRQ, or NMI). Unfortunately, userspace can stuff MP_STATE and/or injected events, and thus put the vCPU into what should be an impossible state.

Don't bother trying to preserve the WARN, e.g. with an anti-syzkaller Kconfig, as WARNs can (hopefully) be added in paths where KVM would be violating x86 architecture, e.g. by WARNing if KVM attempts to inject an exception or interrupt while the vCPU isn't running.

CVSS Base Scores

version 3.1