# 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.

- **Severity:** Not scored
- **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:** Yes
- **Published:** 8 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-94640, BELL-CVE-2026-68081, DEBIAN-CVE-2026-68081, GHSA-8ff4-44g5-rp4f, UBUNTU-CVE-2026-68081

## 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.

## Is CVE-2026-68081 being exploited?

There is no known exploitation of CVE-2026-68081 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68081 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-68081 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68081/ (Markdown: https://insights.sbomify.com/CVE-2026-68081/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68081
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68081
- OSV: https://osv.dev/vulnerability/CVE-2026-68081

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68081/
Summaries are generated and may contain mistakes; the official description above is the record.