# CVE-2026-89443

## Summary

- **CVE ID:** CVE-2026-89443
- **Severity:** HIGH
- **CVSS Score:** 7.1 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 14, 2026

## Description

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

platform/x86: ISST: Validate level in perf mask ioctls

isst_if_get_perf_level_mask() and isst_if_get_base_freq_mask() use the
user-provided level as an index into perf_levels[] via
_read_pp_level_info() and _read_bf_level_info(), but neither helper
validates it first.

The adjacent level-info helpers reject levels above max_level before
reading the same per-level register block. Add the same bounds checks to
the mask helpers, and reject disabled SST-PP levels in
isst_if_get_perf_level_mask() to match isst_if_get_perf_level_info().

This prevents out-of-bounds reads from the per-level offset table on
invalid ioctl input.

## Affected Products

- Linux — Linux (ea009e4769fa3bd05d4c111c3b6865eb3a9be829)
- Linux — Linux (6.4)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (6.6.157)

## References

- [CNA](https://git.kernel.org/stable/c/1a8bab5ceee1a42a78de12d3d69f67516a20588e)
- [CNA](https://git.kernel.org/stable/c/1889a9156553f0692acd57caf15e877baace1a01)
- [CNA](https://git.kernel.org/stable/c/d19385624bdfb577db9c94bb8879992fd5e17bcd)
- [CNA](https://git.kernel.org/stable/c/80e0d353c86a9a168ad6d213f494796294381538)
- [CNA](https://git.kernel.org/stable/c/beb22ebf76c0415f22d2d0c3f1ff0627e7ae4a68)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.16%
- **EPSS Percentile:** 5.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._