platform/x86: ISST: Validate logical CPU id and clos id (CVE-2026-89438) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89438

platform/x86: ISST: Validate logical CPU id and clos id

Answer in brief

CVE-2026-89438 records a Unknown severity vulnerability in platform/x86: ISST: Validate logical CPU id and clos id. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Sep 11, 2026Source checked Sep 11, 2026First seen by HOL Sep 11, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=12a7d2cb811dd8a884dea088a2701fcb8d00136e <c9ee2770eb95ba316a56d776b2b66666b70c194b \|\| >=12a7d2cb811dd8a884dea088a2701fcb8d00136e <5b032e1dda486ca41d10536bd195bd8a559af1e2 \|\| >=12a7d2cb811dd8a884dea088a2701fcb8d00136e <82d4afadb02fb4d7d7bb9230900904c10e49ec87 \|\| >=12a7d2cb811dd8a884dea088a2701fcb8d00136e <124e2dbabe460c2a6e7440f4ad8af560131295c9	c9ee2770eb95ba316a56d776b2b66666b70c194b, 5b032e1dda486ca41d10536bd195bd8a559af1e2, 82d4afadb02fb4d7d7bb9230900904c10e49ec87, 124e2dbabe460c2a6e7440f4ad8af560131295c9
Linux/Linuxgeneric	6.4	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to c9ee2770eb95ba316a56d776b2b66666b70c194b if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.