Out-of-bounds write in Linux kernel - CVE-2026-63957

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Main Vulnerability Database Vulnerabilities #VU138694

Out-of-bounds write in Linux kernel - CVE-2026-63957

Published: July 20, 2026


Vulnerability identifier: #VU138694
CSH Severity: Medium
CVSS v4: 5.1 [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]
CVE-ID: CVE-2026-63957
CWE-ID: CWE-787
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows an attacker with physical access to cause memory corruption.

The vulnerability exists due to memory corruption in the safe_serial USB serial driver when processing a malicious USB device that reports a bulk-out endpoint size smaller than eight bytes in safe mode. An attacker with physical access can connect a crafted USB device to cause memory corruption.

Exploitation requires the target system to interact with a malicious USB device operating in safe mode.


Affected software

Linux kernel
Ubuntu
linux-ibm (Ubuntu package)
linux-azure (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-63957

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

External References

Related Security Bulletins