CVE-2026-31655 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution maintainers, and users of Linux-based systems should review and apply patches to ensure the NOC_HDCP clock remains enabled. These stakeholders are impacted as they are responsible for maintaining and securing Linux kernel deployments. They should verify the Linux kernel version, monitor system logs for potential hangs, and apply patches to prevent potential hangs caused by the NoC ADB400 port The

Why it matters

The Linux kernel vulnerability could potentially cause a hang due to the NoC ADB400 port power down handshake if the NOC_HDCP clock is disabled. Defenders should review and apply patches to ensure the NOC_HDCP clock remains enabled, verify the Linux kernel version, and monitor system logs for potential hangs.

• Verify NOC_HDCP clock status to prevent potential hangs
• Apply patches to ensure the NOC_HDCP clock remains enabled
• Monitor system logs for potential hangs caused by the NoC ADB400 port power down handshake
• Review Linux kernel versions for vulnerability

Technical summary

The Linux kernel vulnerability could potentially cause a hang due to the NoC ADB400 port power down handshake if the NOC_HDCP clock is disabled. The vulnerability has been resolved by keeping the NOC_HDCP clock always enabled. This change ensures that the NOC_HDCP clock remains active, preventing potential hangs in Linux kernel deployments. The vulnerability affects Linux kernel versions and requires patching to ensure the NOC_HDCP clock remains enabled. Defenders should review and apply patches to prevent potential hangs.

Defensive priority

Apply patches to ensure the NOC_HDCP clock remains enabled

Recommended defensive actions

• Review and apply patches to ensure the NOC_HDCP clock remains enabled
• Verify the Linux kernel version and apply patches if necessary
• Monitor system logs for potential hangs caused by the NoC ADB400 port power down handshake
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD detail page provide information on the vulnerability, including its description and affected versions. The vulnerability has been resolved by keeping the NOC_HDCP clock always enabled. However, the specific versions of the Linux kernel affected and the exact impact on various deployments are not detailed. Defenders should verify the Linux kernel version and review system logs for potential hangs. The official CVE Program record and NVD detail page serve as primary sources for this 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.