Executive brief
The Linux kernel's AMD display driver contains a null pointer dereference vulnerability in its HDCP (High-bandwidth Digital Content Protection) configuration routine. When a display transitions between states, the code could attempt to configure HDCP without first validating that a valid video stream exists, potentially causing system crashes or instability. This is a kernel stability issue that could affect systems with AMD GPUs during normal display state changes.
Technical details
The vulnerability is a null pointer dereference in the `update_config()` function within the AMD display driver's HDCP module (amdgpu_dm_hdcp.c). The root cause is that during display transition states, the function directly dereferences `config->dm_stream_ctx` and uses it to access the `dc_link` and other structures without validating that these pointers are valid. The fix adds a NULL check after assignment: if `aconnector` is NULL or `aconnector->dc_link` is NULL, the function returns early, skipping invalid HDCP configuration attempts. Attack vector is local (local denial of service via display state changes), requires no special privileges, and the fix is available in upstream Linux kernel commits.
Affected products
- Linux Linux kernel multiple versions affected (patched in stable series)
Timeline
- 2026-09-11: disclosed: CVE published
- 2026-06-24: patched: Upstream fix committed by Fangzhi Zuo
- 2026-09-07: patched: Backported to stable kernel series