---
id: CVE-2026-68274
title: 'drm/xe/guc: Fix buffer overflow in steered register list allocation'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drm/xe/guc: Fix buffer overflow in steered register list allocation

  The size calculation for the steered register extarray uses only the
  geometry DSS mask (g_dss_mask)…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= b170d696c1e2226713471d810c63b1162335079f <
    b485bfb45555163bfa5f565d6a3415fcb3035b02
  - >-
    Linux >= b170d696c1e2226713471d810c63b1162335079f <
    a9a020f3c11eba6573b699f9cf9245a51b025ade
  - >-
    Linux >= b170d696c1e2226713471d810c63b1162335079f <
    632ecc90e1ca5d3b6822bb4d08f84a175b6c42c0
  - Linux 6.13
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:46:31.440786Z'
published: '2026-08-10'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:53:05.971Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-68274'
references:
  - url: 'https://git.kernel.org/stable/c/b485bfb45555163bfa5f565d6a3415fcb3035b02'
  - url: 'https://git.kernel.org/stable/c/a9a020f3c11eba6573b699f9cf9245a51b025ade'
  - url: 'https://git.kernel.org/stable/c/632ecc90e1ca5d3b6822bb4d08f84a175b6c42c0'
tags:
  - cve.org
epss: 0.00151
epssPercentile: 0.03832
ingestedAt: '2026-10-16T17:24:46.853Z'
---

## Overview

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

drm/xe/guc: Fix buffer overflow in steered register list allocation

The size calculation for the steered register extarray uses only the
geometry DSS mask (g_dss_mask) to determine the number of entries to
allocate:

  total = bitmap_weight(gt->fuse_topo.g_dss_mask, ...) * steer_reg_num;

However, the filling loop uses for_each_dss_steering(), which iterates
over for_each_dss(), defined as the union of g_dss_mask and c_dss_mask
(geometry + compute DSS). On platforms with compute-only DSS bits, the
loop writes past the allocated buffer, corrupting adjacent slab objects.

This manifests as list_del corruption and SLUB redzone overwrites during
drm_managed_release on device unbind, since the overflow corrupts the
drmres list_head of neighboring allocations.

Fix by computing the allocation size using the union of both DSS masks,
matching the iteration pattern of for_each_dss_steering().

--
v2:
- use bitmap_weighted_or() (Zhanjun)

(cherry picked from commit 0a78a44f4901aa6c9263e66be7fce02282f1109f)

## Affected

- `Linux >= b170d696c1e2226713471d810c63b1162335079f < b485bfb45555163bfa5f565d6a3415fcb3035b02`
- `Linux >= b170d696c1e2226713471d810c63b1162335079f < a9a020f3c11eba6573b699f9cf9245a51b025ade`
- `Linux >= b170d696c1e2226713471d810c63b1162335079f < 632ecc90e1ca5d3b6822bb4d08f84a175b6c42c0`
- `Linux 6.13`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.