# CVE-2026-68206: media: v4l2-ctrls: validate HEVC active reference counts

> Missing validation of HEVC reference counts in the Linux kernel media subsystem can lead to driver instability or 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-2026-68206, DEBIAN-CVE-2026-68206, GHSA-qx89-rcg9-ghw4, UBUNTU-CVE-2026-68206

## What is CVE-2026-68206?

CVE-2026-68206 is a high-severity 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:

media: v4l2-ctrls: validate HEVC active reference counts

HEVC slice parameters are shared stateless V4L2 controls, but the common
validation path does not verify the active L0/L1 reference counts before
driver-specific code consumes them.

The original report came from Cedrus, but the active count bounds are
not Cedrus-specific. Validate them in the common HEVC slice control path
so stateless HEVC drivers get the same basic guarantees as soon as the
control is queued.

Do not reject ref_idx_l0/ref_idx_l1 entries here. Existing userspace may
use out-of-range sentinel values such as 0xff for missing references, and
some hardware can use that information for concealment. Keep this common
check limited to the active reference counts.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-68206?


## How do I fix CVE-2026-68206?

Apply the vendor's patch.

## Is CVE-2026-68206 being exploited?

There is no known exploitation of CVE-2026-68206 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68206 and fix it if it is affected.

What it is: CVE-2026-68206 is a high-severity 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-2026-68206 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-2026-68206/ (Markdown: https://insights.sbomify.com/CVE-2026-68206/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68206
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68206
- OSV: https://osv.dev/vulnerability/CVE-2026-68206

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68206/
Summaries are generated and may contain mistakes; the official description above is the record.