CVE-2026-63964 usb: typec: ucsi: ccg: reject firmware images without a ':' record header

Q: Is CVE-2026-63964 being exploited?

There is no known exploitation of CVE-2026-63964 in the wild and no public exploit code.

Not scored Published 19 Jul 2026 Updated 20 Jul 2026

A local root user can crash the Linux kernel by providing a malformed firmware image to the UCSI CCG driver due to a null pointer dereference.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-63964?

CVE-2026-63964 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: typec: ucsi: ccg: reject firmware images without a ':' record header

do_flash() locates the first .cyacd record with

p = strnchr(fw->data, fw->size, ':'); while (p < eof) { s = strnchr(p + 1, eof - p - 1, ':'); ... }

If the firmware image contains no ':' byte, strnchr() returns NULL. NULL compares less than the valid kernel pointer eof, so the loop body runs and strnchr() is called with p + 1 == (void *)1 and a length of roughly (unsigned long)eof, causing a wonderful crash.

The not_signed_fw fallthrough earlier in do_flash() and the chip-state branches in ccg_fw_update_needed() allow an unsigned blob to reach this loop, so a root user who can place a crafted file under /lib/firmware and write the do_flash sysfs attribute can trigger the oops.

Bail out with -EINVAL when the initial strnchr() returns NULL.

Which versions are affected by CVE-2026-63964?

How do I fix CVE-2026-63964?

Apply the vendor's patch.

Is CVE-2026-63964 being exploited?