CVE-2026-89438 platform/x86: ISST: Validate logical CPU id and clos id
A missing validation in the Linux kernel ISST driver allows privileged users to trigger invalid MMIO offsets, potentially causing system crashes or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89438?
CVE-2026-89438 is a missing authorization vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
platform/x86: ISST: Validate logical CPU id and clos id
Validate max CLOS ID and logical CPU ID for core power feature. Reject any clos level or logical CPU number greater than the supported maximum. These are used to calculate MMIO offset.
Which versions are affected by CVE-2026-89438?
How do I fix CVE-2026-89438?
Apply the vendor's patch.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-89438 being exploited?
There is no known exploitation of CVE-2026-89438 in the wild and no public exploit code.
Sources
Also known as AZL-100674, BELL-CVE-2026-89438, DEBIAN-CVE-2026-89438, GHSA-vpjv-6qfx-qxxr, UBUNTU-CVE-2026-89438.