# CVE-2026-21734: GPU DDK - libusc OOB write at TreeRemove during WebGPU shader compilation

> A malicious web page can trigger an out-of-bounds write in the GPU shader compiler, potentially leading to code execution or privilege escalation on affected devices.

- **Severity:** High 7.7 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Jun 2026
- **Updated:** 26 Jun 2026
- **Also known as:** A-473852583, ASB-A-473852583, GHSA-c5qr-j92g-m289

## What is CVE-2026-21734?

CVE-2026-21734 is a high-severity memory corruption vulnerability in Imagination Technologies Graphics DDK, published on 26 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A web page that contains unusual GPU shader code is loaded into the GPU compiler process and can trigger a write out-of-bounds write crash in the GPU shader compiler library. On certain platforms, when the compiler process has system privileges this could enable further exploits on the device.

An edge case using a very small value in GPU shader code can cause a segmentation fault in the GPU shader compiler due to am out-of-bounds write.

Weakness: CWE-823 (Use of Out-of-range Pointer Offset)

## Which versions are affected by CVE-2026-21734?

It affects 1 product.


Products: Imaginationtech Ddk.

## How do I fix CVE-2026-21734?

Apply the vendor's patch.

## Is CVE-2026-21734 being exploited?

There is no known exploitation of CVE-2026-21734 in the wild and no public exploit code.

## Other vulnerabilities in Imagination Technologies Graphics DDK

- [CVE-2026-16280](https://insights.sbomify.com/CVE-2026-16280/): GPU DDK - Integer overflow in _PMRLogicalOffsetToPhysicalOffset (critical 9.8)
- [CVE-2025-13952](https://insights.sbomify.com/CVE-2025-13952/): GPU DDK - libusc UAF via WebGPU shaders at MergeConsecutiveBarriersBP (critical 9.8)
- [CVE-2026-21732](https://insights.sbomify.com/CVE-2026-21732/): GPU DDK - libusc OOB write at ConvertSwitchToArrayLookupBP during WebGPU shader compilation (critical 9.6)
- [CVE-2025-25176](https://insights.sbomify.com/CVE-2025-25176/): GPU DDK - GPU Register value contents leaked from secure workloads to non-secure world (critical 9.1)
- [CVE-2025-58411](https://insights.sbomify.com/CVE-2025-58411/): GPU DDK - Reservation::psMappedPMR can change while used by a freelist -> UAF (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-21734 and fix it if it is affected.

What it is: CVE-2026-21734 is a high-severity memory corruption vulnerability in Imagination Technologies Graphics DDK, published on 26 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-2026-21734 in the wild and no public exploit code.

Affected product: Imagination Technologies Graphics DDK. 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-2026-21734/ (Markdown: https://insights.sbomify.com/CVE-2026-21734/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21734
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-21734
- OSV: https://osv.dev/vulnerability/CVE-2026-21734

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-21734/
Summaries are generated and may contain mistakes; the official description above is the record.