CVE-2026-63964

usb: typec: ucsi: ccg: reject firmware images without a ':' record header

Published Jul 19, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8593-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8603-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8618-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8663-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8664-1 Linux kernel (NVIDIA BaseOS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-3 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-8875-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8877-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8878-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8879-1 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-8903-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8904-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8905-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8906-1 Linux kernel (IBM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8875-2 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8903-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8905-2 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-9002-1 Linux kernel (NVIDIA Tegra) vulnerabilities
Ubuntu USN Ubuntu USN USN-9025-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9029-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-9066-1 Linux kernel (HWE) vulnerabilities
History
Type Values Removed Values Added
CPEs cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low

Type Values Removed Values Added
Weaknesses CWE-476
Type Values Removed Values Added
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.
Title usb: typec: ucsi: ccg: reject firmware images without a ':' record header
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Jul 20, 2026, 6:41 AM
Reserved
Jul 19, 2026, 7:54 AM
Status
Analyzed
Published
Jul 19, 2026, 4:17 PM
Modified
Oct 30, 2026, 5:29 PM
Severity
Low
Public date
Jul 19, 2026, 12:00 AM