CVE-2026-89916

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine without logging in. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-09-11 19:38 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-09-16 11:17 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-10-19 09:18 UTC Last updatedMost recent change to the record

Details

Published

2026-09-16 11:17 UTC

Last modified

2026-10-19 09:18 UTC

Exploit probability

0.2% · EPSS, next 30 days

Record status

Received

Attack profile CVSS 3.1 · 9.3

Attack vector

Local

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High