CVE-2026-63958 usb: typec: ucsi: validate connector number in ucsi_connector_change()
A malicious USB controller can trigger out-of-bounds memory access in the Linux kernel UCSI driver, potentially causing crashes or code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-63958?
CVE-2026-63958 is a memory corruption vulnerability in Linux, published on 19 Jul 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_connector_change()
The connector number in a UCSI CCI notification is a 7-bit field supplied by the PPM. ucsi_connector_change() uses it to index the ucsi->connector[] array without checking it against the number of connectors the PPM reported at init time, so a buggy or malicious PPM (EC firmware, or an I2C-attached UCSI controller on the ccg / stm32g0 / glink transports) can drive schedule_work() on memory past the end of the array.
Reject connector numbers that are zero or exceed cap.num_connectors before dereferencing the array.
Which versions are affected by CVE-2026-63958?
How do I fix CVE-2026-63958?
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-2026-63958 being exploited?
There is no known exploitation of CVE-2026-63958 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-63958, DEBIAN-CVE-2026-63958, GHSA-qx25-w5h5-ch8m, ROOT-OS-DEBIAN-11-CVE-2026-63958, ROOT-OS-UBUNTU-2204-CVE-2026-63958, UBUNTU-CVE-2026-63958.