CVE-2026-74387 Linux CVE debrief

Who should care

System administrators and security teams responsible for Linux-based systems should assess their exposure and prioritize patching vulnerable systems. This includes teams managing Linux kernel configurations, ALSA sequencer MIDI output path deployments, and those responsible for maintaining system security and integrity. Additionally, operators and platform administrators should review the vulnerability's impact on their environments and take necessary rem

Why it matters

This vulnerability in the Linux kernel's ALSA sequencer MIDI output path could allow local attackers to elevate privileges or cause denial of service. System administrators and security teams should assess exposure and prioritize patching.

• Local attackers could exploit this vulnerability to elevate privileges
• Denial of service could occur due to NULL-deref or use-after-free
• System crashes or instability might result from exploitation

Technical summary

The Linux kernel vulnerability (CVE-2026-74387) is caused by a race condition in the ALSA sequencer MIDI output path. This condition can lead to a NULL-deref or use-after-free. The issue arises because event_process_midi() borrows msynth->output_rfile.output and then passes the substream to dump_midi() and snd_rawmidi_kernel_write() without synchronizing with the output open/close transition. The vulnerability affects Linux-based systems, particularly those with ALSA sequencer MIDI output configurations. The fix involves adding synchronization to prevent the race condition.

Defensive priority

High

Recommended defensive actions

• Review and apply the provided kernel patches to address the vulnerability
• Ensure systems are updated with the latest Linux kernel versions
• Monitor system logs for potential exploitation attempts
• 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 associated source item provide details on the vulnerability, including a description of the issue and affected versions. However, specific exploitation details or victim information are not provided.

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.