CVE-2026-89739 Linux CVE debrief

Who should care

Linux kernel maintainers, users, and administrators should assess exposure and prioritize verification of affected systems. Affected operator, platform, vulnerability-management, and security-team impact should be evaluated to ensure proper mitigation and remediation.

Why it matters

A use-after-free vulnerability exists in the Linux kernel's USB DWC3 gadget driver, which could lead to system crashes or potential code execution. Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems.

• Verify Linux kernel versions and configurations for potential exposure
• Assess system updates and patches for the Linux kernel
• Monitor system logs for suspicious activity related to the USB DWC3 gadget driver

Technical summary

The Linux kernel's USB DWC3 gadget driver is vulnerable to a use-after-free bug due to a race condition between the `dwc3_gadget_free_endpoints` function and the `dwc3_nostream_work` delayed work. This occurs when a DEPEVT_STREAM_NOSTREAM event is received, and the `dwc3_gadget_endpoint_stream_event` function queues the `dwc3_nostream_work` delayed work on the system_percpu_wq. If the gadget is removed, the `dwc3_gadget_free_endpoints` function cleans up and releases the memory allocated for the endpoint, but the delayed work may still be pending or running, leading to a use-after-free bug. The vulnerability could lead to system crashes or potential code execution.

Defensive priority

Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems.

Recommended defensive actions

• Review Linux kernel versions and configurations for potential exposure
• Verify system updates and patches for the Linux kernel
• Monitor system logs for suspicious activity related to the USB DWC3 gadget driver
• Assess system updates and patches for the Linux kernel
• Verify Linux kernel versions and configurations for potential exposure
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, but the scope of affected systems and versions is not explicitly stated. To verify exposure, defenders should review Linux kernel versions and configurations, assess system updates and patches, and monitor system logs for suspicious activity related to the USB DWC3 gadget driver. Evidence is limited to public CVE details and NVD assessments; further verification is required to confirm affected systems.

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.