# CVE-2026-68445: drm/vc4: Prevent shader BO mappings from becoming writable

> Attackers can bypass GPU shader validation by making read-only mappings writable, potentially executing malicious code or escalating privileges.

- **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:** 12 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-68445, DEBIAN-CVE-2026-68445, GHSA-rw5p-xff5-86qj, UBUNTU-CVE-2026-68445

## What is CVE-2026-68445?

CVE-2026-68445 is a high-severity vulnerability in Linux, published on 12 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/vc4: Prevent shader BO mappings from becoming writable

vc4_gem_object_mmap() rejects a writable mapping of a validated shader
BO, but leaves VM_MAYWRITE set.  Userspace can map the BO read-only and
then turn it writable with mprotect().

Validated shader BOs must stay read-only: the validator checks the
instructions once and the GPU trusts them afterwards.  A writable
mapping lets userspace rewrite the code after validation, bypassing the
validator.

Clear VM_MAYWRITE on the read-only path so the mapping cannot be
upgraded, as i915 already does for its read-only objects.

## Which versions are affected by CVE-2026-68445?


## How do I fix CVE-2026-68445?

Apply the vendor's patch.

## Is CVE-2026-68445 being exploited?

There is no known exploitation of CVE-2026-68445 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68445 and fix it if it is affected.

What it is: CVE-2026-68445 is a high-severity vulnerability in Linux, published on 12 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-2026-68445 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-2026-68445/ (Markdown: https://insights.sbomify.com/CVE-2026-68445/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68445
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68445
- OSV: https://osv.dev/vulnerability/CVE-2026-68445

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68445/
Summaries are generated and may contain mistakes; the official description above is the record.