Out-of-bounds write in Linux kernel - CVE-2026-63899
Published: July 20, 2026
Vulnerability identifier: #VU138752
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-2026-63899
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 memory corruption in the mxuport USB serial driver when handling a malicious USB device that reports a bulk-out endpoint max packet size smaller than eight bytes. An attacker with physical access can attach a crafted device to cause memory corruption.
How to mitigate CVE-2026-63899
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/086b858b5f5125bc9d967ea2bd825f83d9f8f29d
- https://git.kernel.org/stable/c/2f3661eb2446e1ef593da45e01a3b21a906768ec
- https://git.kernel.org/stable/c/4085f0dbb1ce2251c9a5938d693de6593f0ab2bd
- https://git.kernel.org/stable/c/6c0cf56f00f280d72180bb6ce79741bc787a6269
- https://git.kernel.org/stable/c/b40166b4ef96067620a0f248e74ad9658c8f680c
- https://git.kernel.org/stable/c/be3a1ed4ae51fa8dde57383277d336ce834f2cd9
- https://git.kernel.org/stable/c/ccbec56f2f9af008f1574335cc6a668f16603e47
- https://git.kernel.org/stable/c/e906545641d34fb1a09a65b4b5cfdff40eb09681