# CVE-2021-4460: drm/amdkfd: Fix UBSAN shift-out-of-bounds warning

> An undefined shift operation in the AMD KFD driver can cause a kernel crash, requiring a patch to prevent denial of service.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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:** 1 Oct 2025
- **Updated:** 11 Aug 2026
- **Also known as:** DEBIAN-CVE-2021-4460, GHSA-qxqc-pxc7-f648, UBUNTU-CVE-2021-4460

## What is CVE-2021-4460?

CVE-2021-4460 is a high-severity vulnerability in Linux kernel, published on 1 Oct 2025. 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/amdkfd: Fix UBSAN shift-out-of-bounds warning

If get_num_sdma_queues or get_num_xgmi_sdma_queues is 0, we end up
doing a shift operation where the number of bits shifted equals
number of bits in the operand. This behaviour is undefined.

Set num_sdma_queues or num_xgmi_sdma_queues to ULLONG_MAX, if the
count is >= number of bits in the operand.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1472

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2021-4460?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-4460?

Apply the vendor's patch.

## Is CVE-2021-4460 being exploited?

There is no known exploitation of CVE-2021-4460 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-2021-4460 and fix it if it is affected.

What it is: CVE-2021-4460 is a high-severity vulnerability in Linux kernel, published on 1 Oct 2025. 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-2021-4460 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-2021-4460/ (Markdown: https://insights.sbomify.com/CVE-2021-4460/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-4460
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-4460
- OSV: https://osv.dev/vulnerability/CVE-2021-4460

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-4460/
Summaries are generated and may contain mistakes; the official description above is the record.