Improper input validation in Linux kernel - CVE-2026-63964
Published: July 20, 2026
Vulnerability identifier: #VU138684
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-63964
CWE-ID: CWE-20
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local privileged user to cause a denial of service.
The vulnerability exists due to improper input validation in the do_flash() function in the ucsi_ccg driver when parsing a crafted firmware image without a ':' record header. A local privileged user can place a crafted firmware file under /lib/firmware and write to the do_flash sysfs attribute to cause a denial of service.
The issue can be triggered by an unsigned firmware blob reaching the flashing logic.
How to mitigate CVE-2026-63964
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/2f395ca1263bd181995eb829f5943a83a20db213
- https://git.kernel.org/stable/c/3f432b8203066c26770fe6ea591361f10021dd6b
- https://git.kernel.org/stable/c/6526f8684f72391138353642af908803ba70795e
- https://git.kernel.org/stable/c/a38ed87818b2419090fb1a6338ddce6842b65dfa
- https://git.kernel.org/stable/c/b41dfc033fe594e152648050e95b9489cd53e9e3
- https://git.kernel.org/stable/c/c4ee519b06389e59ba2d6aa722fcc4a02a8bbcbb
- https://git.kernel.org/stable/c/c8460de584fe5415d212cfdd127d4db90835a450
- https://git.kernel.org/stable/c/d7486952bf74e546ee3748fb14b2d07881fa6273