CVEvulnerability
CVE-2026-63964
- Status
- Undergoing Analysis
- Published
- 2026-07-19
- Last modified
- 2026-07-30
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
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.
References
- https://git.kernel.org/stable/c/2f395ca1263bd181995eb829f5943a83a20db213 git.kernel.org
- https://git.kernel.org/stable/c/3f432b8203066c26770fe6ea591361f10021dd6b git.kernel.org
- https://git.kernel.org/stable/c/6526f8684f72391138353642af908803ba70795e git.kernel.org
- https://git.kernel.org/stable/c/a38ed87818b2419090fb1a6338ddce6842b65dfa git.kernel.org
- https://git.kernel.org/stable/c/b41dfc033fe594e152648050e95b9489cd53e9e3 git.kernel.org
- https://git.kernel.org/stable/c/c4ee519b06389e59ba2d6aa722fcc4a02a8bbcbb git.kernel.org
- https://git.kernel.org/stable/c/c8460de584fe5415d212cfdd127d4db90835a450 git.kernel.org
- https://git.kernel.org/stable/c/d7486952bf74e546ee3748fb14b2d07881fa6273 git.kernel.org