CVE-2026-89915

Last refreshed2026-10-19

Status: UPDATED | Advisory ID: CVE-2026-89915

Key Details

CVE	CVE-2026-89915
CVSS Score / Version	9.3 (Critical) / CVSS v3.1
Updated	2026-10-19
CVSS Vector	`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`
CVSS Prose	attack vector is local; attack complexity is low; privileges required is none; user interaction is none; scope is changed; confidentiality impact is high; integrity impact is high; availability impact is high.
Affected products	Linux Kernel

Vendor	Product	Affected Versions	Patch Status
Linux	Linux Kernel

Vendor

Product

Affected Versions

Patch Status

Linux

Linux Kernel

Subsystems	OT Supporting Infrastructure
Sectors	All Sectors

In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: Remove VM-wide VNCR mapping counter

The global VNCR mapping counter is used to decide whether an L1

provided VNCR page is mapped in L0 on any CPU at the point of

dealing with a TLB invalidation. It is incremented when a mapping

is made in the fixmap, and decremented when unmapped.

As it turns out, this tracking has several flaws:

- we are trying to invalidate TLBs, and the mapping is only an

opportunistic consequence of the TLB. Checking this counter to

decide whether a TLB needs to be invalidated may result in missed

invalidations.

- an L1 vcpu invalidating its own TLB (a very likely case) will not

succeed in invalidating the VNCR pseudo TLB because that page is

not mapped in L0 at this stage.

Given that this tracking fails at delivering the minimum guarantees

that are required and is only a performance optimisation, remove it

completely. (NVD)

Monitor Linux's web page for any future patch releases.

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-89915
CVE	https://www.cve.org/CVERecord?id=CVE-2026-89915

Source

Reference

NVD

CVE