PatchTheCVECVE-2026-85032: The MCTP over USB device class in subsys/pmci/mctp/mctp_usb.c splits RX handling across two threads: the syste
CVE-2026-85032 is a medium-severity flaw (CVSS 4.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
The MCTP over USB device class in subsys/pmci/mctp/mctp_usb.c splits RX handling across two threads: the system workqueue runs mctp_usb_class_out_work(), which parses host OUT data byte by byte and fills a packet buffer at usb->rx_pkt, while the USB device stack thread runs mctp_usb_class_disable(). The disable handler used k_work_cancel(), which removes a queued work item but returns immediately without waiting for a handler that is already runn
Why this priority
- No elevated risk signals yet
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 4.8 (Medium) |
| Attack vector | Physical |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | n/a |
| CISA exploited list | No |
| Weakness | CWE-416 |
| Published | 2026-11-03 |
| Last modified | 2026-11-03 |
Last updated 2026-11-03 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Advisories and coverage
Research and news
- Vulners Bulletins: CVE-2026-85032 2026-11-03
- Vulners Bulletins: CVE-2026-85032 Use-after-free in the MCTP over USB binding when the host disables the class while RX parsing is in progress 2026-11-03
- Vulners Bulletins: CVE-2026-85032 Use-after-free in the MCTP over USB binding when the host disables the class while RX parsing is in progress 2026-11-03
- VulDB Recent Entries: CVE-2026-85032 | ZephyrProject Zephyr up to 4.4.x MCTP mctp_usb.c mctp_usb_class_disable use after free 2026-11-03
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-85032?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-85032 being exploited?
CVE-2026-85032 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-85032 affect?
CVE-2026-85032 affects affected software. Severity is medium (CVSS 4.8). The MCTP over USB device class in subsys/pmci/mctp/mctp_usb.c splits RX handling across two threads: the system workqueue runs mctp_usb_class_out_work(), which parses host OUT data byte by byte and fills a packet buffer at usb->rx_pkt, whil
How urgent is CVE-2026-85032?
Priority 17/100. No elevated risk signals yet.