CVE-2026-46131: KVM: x86: check for nEPT/nNPT in slow flush hypercalls
In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: check for nEPT/nNPT in slow flush hypercalls
Checking isguestmode(vcpu) is incorrect, because translatenestedgpa() is only valid if an L2 guest is running with nested EPT/NPT enabled. Instead use the same condition as translatenestedgpa() itself.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.141.1-1 - Configuration
In KVM for x86 nested virtualization, adjust the nEPT/nNPT validation used by slow flush hypercalls so it matches the condition used by translate_nested_gpa() itself (i.e., the check is only valid when an L2 guest is running with nested EPT/NPT enabled).
KVM x86 nested virtualization nEPT/nNPT check in slow flush hypercalls = Use the same condition as translate_nested_gpa()
Event History
Frequently Asked Questions
What is the severity of CVE-2026-46131?
The severity of CVE-2026-46131 is classified as medium with a score of 5.5.
How do I fix CVE-2026-46131?
To fix CVE-2026-46131, ensure that your Linux kernel and KVM are updated to the latest version that includes the patch.
What software is affected by CVE-2026-46131?
CVE-2026-46131 affects the Linux kernel, specifically the KVM x86 component, and also impacts the Microsoft azl3 kernel 6.6.139.1-1.
What is the impact of CVE-2026-46131 on systems?
CVE-2026-46131 may allow an attacker to exploit vulnerabilities in the hypervisor leading to a denial of service condition.
When was CVE-2026-46131 published?
CVE-2026-46131 was published on May 28, 2026.