CVE-2026-63897 USB: serial: mct_u232: fix missing interrupt-in transfer sanity check
A missing sanity check in the Linux kernel's mct_u232 USB serial driver allows local attackers to leak uninitialized kernel memory to user space.
- 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-2026-63897?
CVE-2026-63897 is a 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: serial: mct_u232: fix missing interrupt-in transfer sanity check
Add the missing sanity check on the size of interrupt-in transfers to avoid parsing stale or uninitialised slab data (and leaking it to user space).
Which versions are affected by CVE-2026-63897?
How do I fix CVE-2026-63897?
Apply the vendor's patch.
Is CVE-2026-63897 being exploited?
There is no known exploitation of CVE-2026-63897 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-63897, DEBIAN-CVE-2026-63897, GHSA-mjxg-c55q-m7j2, ROOT-OS-UBUNTU-2204-CVE-2026-63897, UBUNTU-CVE-2026-63897.