Out-of-bounds write in Linux kernel - CVE-2026-63995
Published: July 20, 2026
Vulnerability identifier: #VU138647
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-63995
CWE-ID: CWE-787
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 an attacker with physical access to cause memory corruption.
The vulnerability exists due to an out-of-bounds write in cmis_fw_update_start_download() when processing a CMIS module firmware management features reply. An attacker with physical access can provide a malicious module response with an oversized start command payload value to cause memory corruption.
A malicious module or a corrupted response can trigger the issue during CMIS firmware update handling.
How to mitigate CVE-2026-63995
Install security update from vendor's repository.