CVE-2026-68235 drm/amd/display: dce100: skip non-DP stream encoders for DP MST
A null pointer dereference in the AMD display driver causes a kernel crash when connecting a second monitor via DisplayPort MST on specific hardware.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-68235?
CVE-2026-68235 is a vulnerability in Linux, published on 10 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: dce100: skip non-DP stream encoders for DP MST
On DCE8-class ASICs (e.g. Bonaire), the resource pool contains digital DIG stream encoders plus one analog DAC encoder. When assigning a stream encoder for a second DisplayPort MST stream, if the preferred digital encoder is already acquired, dce100_find_first_free_match_stream_enc_for_link() falls back to the first free pool entry. That entry may be the analog encoder, whose funcs table lacks DP hooks such as dp_set_stream_attribute. The subsequent atomic commit then dereferences NULL function pointers in link_set_dpms_on() and crashes.
Skip encoders without dp_set_stream_attribute when the stream uses a DP signal (including MST). Use dc_is_dp_signal(stream->signal) for the MST fallback path instead of checking only the link connector signal.
Tested on: - GPU: AMD Radeon R7 260X (Bonaire / DCE8) - Board: Supermicro C9X299-PG300 - Setup: DP MST daisy chain, hotplug second monitor or have it connected on boot - Kernel: 7.1.3 (issue observed since 6.19) - Result: kernel oops without patch; dual monitors stable with patch
(cherry picked from commit 28ec64943e3ee4d9b8d30cea61e380f1429953a8)
Which versions are affected by CVE-2026-68235?
How do I fix CVE-2026-68235?
Apply the vendor's patch.
Is CVE-2026-68235 being exploited?
There is no known exploitation of CVE-2026-68235 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-68235, GHSA-23xc-5vxv-wj6v, UBUNTU-CVE-2026-68235.