CVE-2026-89438: platform/x86: ISST: Validate logical CPU id and clos id

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-11 · updated 2026-10-19

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.

Affected products

Linux kernel: 6.4 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/0d601126c7afda9bb94dfecc8b2c0a16f20d76cb
https://git.kernel.org/stable/c/124e2dbabe460c2a6e7440f4ad8af560131295c9
https://git.kernel.org/stable/c/5b032e1dda486ca41d10536bd195bd8a559af1e2
https://git.kernel.org/stable/c/82d4afadb02fb4d7d7bb9230900904c10e49ec87
https://git.kernel.org/stable/c/c9ee2770eb95ba316a56d776b2b66666b70c194b

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