Out-of-bounds read in Linux kernel - CVE-2026-63892

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Main Vulnerability Database Vulnerabilities #VU138759

Out-of-bounds read in Linux kernel - CVE-2026-63892

Published: July 20, 2026


Vulnerability identifier: #VU138759
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63892
CWE-ID: CWE-125
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to an out-of-bounds read and integer underflow in __tb_property_parse_dir() in the thunderbolt property parser when parsing a crafted non-root property directory with dir_len less than 4. A local user can provide crafted property data to trigger out-of-bounds memory access and cause a denial of service.

The issue affects the non-root parsing path, where a short directory length can cause a UUID copy to read past the end of the property block and can also cause entry walking to continue out of bounds until the kernel oopses.


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-2026-63892

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