In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: guard dc_sink dereferences in MST mode validation… (CVE-2026-98786)

The vulnerability in the Linux kernel's AMD display driver involves unsafe dereferences of the dc_sink pointer in MST (Multi-Stream Transport) mode validation. Specifically, dm_dp_mst_is_port_support_mode() and get_conv_frl_bw() functions read fields from dc_sink without NULL checks. Since dc_sink can be asynchronously cleared during MST unplug, these accesses can race with teardown operations, potentially causing use-after-free or NULL pointer dereferences. The patch introduces checks to fail port-support validation and skip FRL conversion paths when dc_sink is absent, preventing unsafe memory access.

The vulnerability could lead to kernel crashes or undefined behavior due to dereferencing a NULL or freed pointer during MST mode validation in the AMD display driver. This may affect system stability or cause denial of service. There is no indication of privilege escalation or code execution from the provided data.

A fix has been applied to the Linux kernel to add proper NULL checks on dc_sink dereferences during MST mode validation. Users should update to the patched kernel version containing commit 7c3db8da4e039698ae198c870712428644e965c7 or later. No additional mitigation steps are indicated.