CVE-2026-108952 RT-Thread CVE debrief

Who should care

Defenders responsible for RT-Thread systems, particularly those using USB CDC VCOM Driver, should assess exposure and prioritize patching or mitigations. This includes operators, platform administrators, and security teams who manage or monitor systems that may be affected by this vulnerability. They should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance, and plan vendor-supported updates or 3rd

Why it matters

Defenders should care about CVE-2026-108952 because it can cause denial of service in RT-Thread systems using the USB CDC VCOM Driver. Exposure assessment and patching or mitigations are necessary.

• Denial of service due to memory corruption
• Potential for system instability or crashes
• Need for verification of exposed systems and USB device configurations
• Priority for applying patches or mitigations

Technical summary

The vulnerability is caused by aliasing rx_ringbuffer as a Serial V2 rt_serial_rx_fifo in _function_enable(). A connected USB host configuring the CDC device triggers writes past the ring buffer into struct vcom members and an invalid rt_free() on close. This occurs because the legacy USB CDC virtual COM port driver does not properly validate or handle the USB host's configuration requests. The vulnerability can lead to denial of service and potential system instability. Defenders should prioritize verifying exposed systems, assessing USB device configurations, and applying patches or mitigations.

Defensive priority

Defenders should prioritize verifying exposed systems, assessing USB device configurations, and applying patches or mitigations.

Recommended defensive actions

• Verify exposed systems and assess USB device configurations
• Apply patches or mitigations from RT-Thread
• Monitor for denial of service conditions
• 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 vulnerability is described in the CVE Program record and NVD vulnerability detail page. Additional information is available from supplemental sources, including issue-tracking, patch, and technical-description references.

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.