CVE-2026-68235

Received Received - Intake

Null Pointer Dereference in AMD Display Engine Driver

Publication date: 2026-08-10

Last updated on: 2026-08-18

Assigner: kernel.org

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)

CVSS Scores

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Meta Information

Published

2026-08-10

Last Modified

2026-08-18

Generated

2026-08-31

AI Q&A

2026-08-10

EPSS Evaluated

2026-08-29

NVD

CVE-2026-68235

EUVD

EUVD-2026-55336

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	7.1.3
linux	linux_kernel	6.19

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a Linux kernel vulnerability affecting AMD display drivers. It occurs when assigning a second DisplayPort MST stream on certain AMD GPUs (DCE8-class like Bonaire). The system may crash due to NULL function pointer dereference when falling back to an analog encoder lacking DP hooks.

Detection Guidance

This vulnerability is specific to AMD GPU hardware and Linux kernel interactions. Detection requires checking kernel logs for crashes related to DisplayPort MST streams on DCE8-class ASICs like Bonaire. Monitor for kernel oops messages during DP MST operations.

Impact Analysis

If you use an affected AMD GPU (e.g., Radeon R7 260X) with DisplayPort MST setups, connecting a second monitor may cause a kernel crash (oops). This leads to system instability or reboot. The issue appears during hotplug or boot with dual monitors.

Compliance Impact

This vulnerability causes kernel crashes due to NULL pointer dereferences in AMD display driver code. It does not directly impact data privacy or security controls required by standards like GDPR or HIPAA. However, system instability from crashes could indirectly affect compliance by disrupting logging, monitoring, or secure operations.

Mitigation Strategies

Apply the Linux kernel patch that skips non-DP stream encoders for DP MST. Update to a kernel version containing the fix (e.g., 7.1.3 or later). If using affected AMD hardware, avoid DP MST daisy chains until patched.

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