# CVE-2026-53136: drm/amd/display: Clamp VBIOS HDMI retimer register count to array size

> A malformed VBIOS can cause an out-of-bounds heap write in the AMD display driver, potentially allowing code execution or privilege escalation.

- **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:** 25 Jun 2026
- **Updated:** 29 Jun 2026
- **Also known as:** AZL-90536, BELL-CVE-2026-53136, DEBIAN-CVE-2026-53136, GHSA-rg3c-j3j2-x6pc, ROOT-OS-DEBIAN-11-CVE-2026-53136, ROOT-OS-DEBIAN-12-CVE-2026-53136, ROOT-OS-UBUNTU-2204-CVE-2026-53136, ROOT-OS-UBUNTU-2404-CVE-2026-53136, UBUNTU-CVE-2026-53136

## What is CVE-2026-53136?

CVE-2026-53136 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Jun 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/amd/display: Clamp VBIOS HDMI retimer register count to array size

[Why & How]
The VBIOS integrated info tables (v1_11 and v2_1) contain HdmiRegNum and
Hdmi6GRegNum fields that are used as loop bounds when copying retimer I2C
register settings into fixed-size arrays (dp*_ext_hdmi_reg_settings[9]
and dp*_ext_hdmi_6g_reg_settings[3]). These u8 fields are not validated
before use, so a malformed VBIOS can specify values up to 255, causing an
out-of-bounds heap write during driver probe.

Clamp each register count to the destination array size using min_t()
before the copy loops, in both get_integrated_info_v11() and
get_integrated_info_v2_1().

(cherry picked from commit 5a7f0ef90195940c54b0f5bb85b87da55f038c69)

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

## Which versions are affected by CVE-2026-53136?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53136?

Apply the vendor's patch.

## Is CVE-2026-53136 being exploited?

There is no known exploitation of CVE-2026-53136 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53136 and fix it if it is affected.

What it is: CVE-2026-53136 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Jun 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-2026-53136 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-53136/ (Markdown: https://insights.sbomify.com/CVE-2026-53136/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53136
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53136
- OSV: https://osv.dev/vulnerability/CVE-2026-53136

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53136/
Summaries are generated and may contain mistakes; the official description above is the record.