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

> 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jul 2026
- **Updated:** 20 Jul 2026
- **Also known as:** AZL-92775, BELL-CVE-2026-63964, DEBIAN-CVE-2026-63964, GHSA-7w55-p3p4-26mv, ROOT-OS-UBUNTU-2204-CVE-2026-63964, UBUNTU-CVE-2026-63964

## 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?

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

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63964 and fix it if it is affected.

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

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63964/ (Markdown: https://insights.sbomify.com/CVE-2026-63964/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63964
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63964
- OSV: https://osv.dev/vulnerability/CVE-2026-63964

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63964/
Summaries are generated and may contain mistakes; the official description above is the record.