CVE-2026-31729 usb: typec: ucsi: validate connector number in ucsi_notify_common()
A malicious USB device can trigger an out-of-bounds array access in the Linux kernel UCSI driver, potentially leading to code execution or system crash.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-31729?
CVE-2026-31729 is a high-severity memory corruption vulnerability in Linux kernel, published on 1 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
usb: typec: ucsi: validate connector number in ucsi_notify_common()
The connector number extracted from CCI via UCSI_CCI_CONNECTOR() is a 7-bit field (0-127) that is used to index into the connector array in ucsi_connector_change(). However, the array is only allocated for the number of connectors reported by the device (typically 2-4 entries).
A malicious or malfunctioning device could report an out-of-range connector number in the CCI, causing an out-of-bounds array access in ucsi_connector_change().
Add a bounds check in ucsi_notify_common(), the central point where CCI is parsed after arriving from hardware, so that bogus connector numbers are rejected before they propagate further.
Weakness: CWE-129
Which versions are affected by CVE-2026-31729?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31729?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-31729 being exploited?
There is no known exploitation of CVE-2026-31729 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31729, DEBIAN-CVE-2026-31729, GHSA-77q3-374v-8gp2, ROOT-OS-DEBIAN-11-CVE-2026-31729, ROOT-OS-DEBIAN-12-CVE-2026-31729, ROOT-OS-UBUNTU-2204-CVE-2026-31729 and 2 more.