CVE-2026-89916

9.3 CRITICAL

Published 2026-09-16 · Updated 2026-09-16

AI risk analysis

Summary: The vulnerability allows a virtual CPU (vCPU) to invalidate Translation Lookaside Buffer (TLB) entries while another vCPU is faulting in the same page, leading to potential data corruption or execution of malicious code.
Exploitability: Exploitation requires concurrent access by multiple vCPUs and specific timing conditions. It is moderately difficult due to the need for precise control over vCPU scheduling and TLB invalidation sequences.
Blast radius: If exploited, this vulnerability could lead to significant system instability or security breaches within virtualized environments, affecting multiple virtual machines (VMs).
Prioritized remediation: Update the Linux kernel to a patched version that addresses the VNCR invalidation handling issue.

kernelvirtualizationmmuvcpu

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Make VNCR invalidation participate in MMU invalidation retry A VNCR TLB invalidation can occur on one vcpu while another vcpu is faulting in this same page. Without correctly handling this, we can end up with the following scenario: - vcpu A walks the PTs to translate VNCR - before vcpu A is able to grab the MMU lock to insert the TLB, vcpu B updates the S1 PTs with an invalid entry, and issues a TLBI S1E2 for this VA - vcpu A inserts the TLB for something that is now invalid This isn't a new problem, and we manage S2 by having the MMU notifier to bump up mmu_invalidate_seq on invalidation so that the fault can be replayed. We can perform something similar here, and extend invalidate_vncr_va() to update the same counter, clearly indicating that the context has changed under our feet. This is safe as the invalidation always happen while holding the MMU lock for write, and that we sample the sequence number before walking S1.

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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