---
id: "CVE-2026-98786"
kind: "vulnerability"
aliases: ["CVE-2026-98786"]
title: "Linux amdgpu display: NULL pointer dereference during MST unplug races"
severity: "low"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["amdgpu", "desktop", "linux-kernel", "runtime", "workstation"]
not_affected_if: ["no-amd-gpu", "no-dp-mst"]
published_at: "2026-10-18T16:17:32+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:15:18+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98786", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux amdgpu display: NULL pointer dereference during MST unplug races

A race in the AMD display driver can dereference a cleared DisplayPort MST sink pointer when a monitor is unplugged during mode validation. The likely result is a kernel crash (denial of service); the sources do not describe code execution.

_Summary, check and fix written by a model from the sources; labelled as such._

## Fix

- Update the Linux kernel to a release that includes the upstream commit 7c3db8da4e039698ae198c870712428644e965c7 (the sources do not list fixed kernel versions).

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98786

## From the sources

In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: guard dc_sink dereferences in MST mode validation

dm_dp_mst_is_port_support_mode() reads
aconnector->dc_sink->dsc_caps... for the DSC branch-throughput check,
and get_conv_frl_bw()'s HDMI-PCON FRL-bandwidth path reads
aconnector->dc_sink->edid_caps.max_frl_rate, both without a NULL
check. dc_sink is cleared asynchronously on MST unplug, and both
functions run from paths that the driver's own comments document as
racing that teardown: the connector probe worker's ->mode_valid
callback and a compositor's atomic check, neither of which holds the
MST manager lock that the teardown path uses. The former does have an
existing dsc_aux NULL check, but dsc_aux isn't reliably cleared in
every path that clears dc_sink, so it doesn't cover this.

Fail the port-support check and skip the FRL conversion path when the
sink is already gone.

(cherry picked from commit 7c3db8da4e039698ae198c870712428644e965c7)

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_