CVE-2026-43191 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, system administrators responsible for Linux kernel updates, and security teams should assess exposure and apply patches to prevent potential system hangs. Those responsible for managing Linux kernel deployments should review and implement the necessary updates.

Why it matters

A medium-severity vulnerability was resolved in the Linux kernel, affecting the drm/amd/display component. The issue involves adjusting the PHY FSM transition to prevent the OTG from becoming stuck when disabling TMDS output. Linux kernel developers and maintainers should assess exposure and apply patches to prevent potential system hangs.

• Potential system hangs due to stuck OTG
• Impact on DCHVM's ability to ACK invalidations

Technical summary

The vulnerability affects the drm/amd/display component in the Linux kernel. A backport of a change made for DCN401 was implemented for DCN35 to address an issue where the PHY PLL is turned off when disabling TMDS output, causing the OTG to remain stuck. This transition to PLL_ON needs to be atomic as there's no guarantee that the thread isn't pre-empted or is able to complete before the IOMMU watchdog times out. The OTG being stuck can lead to a hang in the DCHVM's ability to ACK invalidations when it thinks the HUBP is still on but it's not receiving global sync.

Defensive priority

Apply patches to prevent potential system hangs

Recommended defensive actions

• Apply patches from Linux kernel stable branches
• Review system configurations for affected versions
• Monitor system logs for potential issues
• Perform vulnerability assessments
• Implement compensating controls
• Track exceptions and retest remediated assets
• Review relevant monitoring and detection logs

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected versions. The issue is caused by turning off the PHY PLL when disabling TMDS output, which causes the OTG to remain stuck. The backport implementation from dcn401 was made for dcn35 to address this issue. Evidence is limited to public CVE and NVD information.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.