In the Linux kernel’s DRM driver for AMD GPUs, a bug causes the system to crash when a second DisplayPort Multi‑Stream Transport (MST) connection is established. On DCE8 ASICs, the resource pool contains both a digital encoder and an analog DAC encoder. If the first stream uses the digital encoder, the kernel may select the analog encoder for the second stream. Because the analog encoder lacks the dp_set_stream_attribute functions, the kernel dereferences a NULL function pointer during atomic commit and triggers an oops, resulting in an immediate loss of the kernel and a system reboot, effectively denying service.

The flaw applies to all Linux kernels that include the affected DRM code and run on AMD GPUs with DCE8‑class ASICs, such as the Radeon R7 260X (Bonaire) and similar devices. The problem surfaces when the system uses DisplayPort MST in a daisy‑chain configuration or when a second monitor is hot‑plugged. The issue has been present since kernel 6.19 and is fixed in kernel 7.1.3 (and later). No other vendors or hardware classes are referenced in the current description.

The vulnerability is not remotely exploitable; it requires direct control of the local system to force an additional DP MST stream or hot‑plug an extra monitor. It leads to a kernel panic, causing the machine to crash and potentially disrupting availability. With no EPSS score available and the vulnerability not listed in CISA’s KEV catalog, the exploitation likelihood is considered moderate, but the severity of the impact remains high as it results in a service denial.