CVE-2026-68081: KVM: nVMX: Put vmcs12 pages if nested VM-Enter fails due to invalid guest state
In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Put vmcs12 pages if nested VM-Enter fails due to invalid guest state
Put all vmcs12 pages if KVM synthesizes a nested VM-Exit due to invalid guest while emulating VMLAUNCH or VMRESUME. The invalid guest state path doesn't use nestedvmxvmexit() as that API is intended to be used if and only if L2 is active, and the open coded equivalent neglects to put the vmcs12 pages. Failure to put the vmcs12 pages leaks any pinned pages (and/or mappings) if L1 retries VMLAUNCH/VMRESUME.
Note, the !fromvmenter scenario doesn't suffer the same problem, as vmxgetnestedstatepages() only gets/pins/maps the vmcs12 pages if L2 is active, i.e. if a "full" VM-Exit is guaranteed before KVM will retry getting vmcs12 pages.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-68081?
CVE-2026-68081 has a risk score of 27, indicating a significant security vulnerability in the Linux kernel.
How do I fix CVE-2026-68081?
The fix for CVE-2026-68081 involves updating the Linux kernel to the latest patched version.
What systems are affected by CVE-2026-68081?
CVE-2026-68081 affects systems running specific versions of the Linux kernel that utilize KVM for nested virtualization.
What does CVE-2026-68081 involve?
CVE-2026-68081 involves a vulnerability where vmcs12 pages are not properly managed if a nested VM-Enter fails due to invalid guest state.
Is CVE-2026-68081 exploitable remotely?
CVE-2026-68081 may be exploitable if an attacker has access to the virtual machine environment where KVM is implemented.