# CVE-2026-68274: drm/xe/guc: Fix buffer overflow in steered register list allocation

> A buffer overflow in the Linux kernel's Intel Xe GPU driver allows attackers to corrupt memory, potentially leading to code execution or system crashes.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68274, DEBIAN-CVE-2026-68274, GHSA-v84f-f8j3-97q7, UBUNTU-CVE-2026-68274

## What is CVE-2026-68274?

CVE-2026-68274 is a high-severity memory corruption vulnerability in Linux, published on 10 Aug 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:

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)

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-68274?


## How do I fix CVE-2026-68274?

Apply the vendor's patch.

## Is CVE-2026-68274 being exploited?

There is no known exploitation of CVE-2026-68274 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68274 and fix it if it is affected.

What it is: CVE-2026-68274 is a high-severity memory corruption vulnerability in Linux, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-68274 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68274/ (Markdown: https://insights.sbomify.com/CVE-2026-68274/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68274
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68274
- OSV: https://osv.dev/vulnerability/CVE-2026-68274

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68274/
Summaries are generated and may contain mistakes; the official description above is the record.