CVE-2026-68081 KVM: nVMX: Put vmcs12 pages if nested VM-Enter fails due to invalid guest state
A local attacker with guest access can cause a memory leak in the Linux kernel KVM module by triggering a specific nested VM-Enter failure, leading to resource exhaustion.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68081?
CVE-2026-68081 is a memory corruption vulnerability in Linux, published on 8 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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 nested_vmx_vmexit() 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 !from_vmenter scenario doesn't suffer the same problem, as vmx_get_nested_state_pages() 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.
Which versions are affected by CVE-2026-68081?
How do I fix CVE-2026-68081?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-68081 being exploited?
There is no known exploitation of CVE-2026-68081 in the wild and no public exploit code.
Sources
Also known as AZL-94640, BELL-CVE-2026-68081, DEBIAN-CVE-2026-68081, GHSA-8ff4-44g5-rp4f, UBUNTU-CVE-2026-68081.