CVE-2025-71108 usb: typec: ucsi: Handle incorrect num_connectors capability
A Linux kernel USB driver flaw allows buggy firmware to cause system boot failures, requiring a patch to handle invalid connector counts.
- 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-2025-71108?
CVE-2025-71108 is a medium-severity denial of service vulnerability in Linux kernel, published on 14 Jan 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: Handle incorrect num_connectors capability
The UCSI spec states that the num_connectors field is 7 bits, and the 8th bit is reserved and should be set to zero. Some buggy FW has been known to set this bit, and it can lead to a system not booting. Flag that the FW is not behaving correctly, and auto-fix the value so that the system boots correctly.
Found on Lenovo P1 G8 during Linux enablement program. The FW will be fixed, but seemed worth addressing in case it hit platforms that aren't officially Linux supported.
Weakness: CWE-20
Which versions are affected by CVE-2025-71108?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-71108?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-71108 being exploited?
There is no known exploitation of CVE-2025-71108 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-71108, DEBIAN-CVE-2025-71108, GHSA-6q3j-74vv-fx6w, ROOT-OS-UBUNTU-2204-CVE-2025-71108, ROOT-OS-UBUNTU-2404-CVE-2025-71108, UBUNTU-CVE-2025-71108.