Use-after-free in Linux kernel - CVE-2026-64239

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Main Vulnerability Database Vulnerabilities #VU139745

Use-after-free in Linux kernel - CVE-2026-64239

Published: July 27, 2026


Vulnerability identifier: #VU139745
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-2026-64239
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a use-after-free.

The vulnerability exists due to use-after-free in DAMON sysfs tried region directory handling when refreshing scheme tried region directories. A local user can repeatedly request directory refresh operations to cause a use-after-free.

The issue can be reproduced on kernels built with CONFIG_DEBUG_KOBJECT_RELEASE because delayed kobject release callbacks can leave freed region objects referenced from the linked list during directory regeneration.


Affected software

Linux kernel
Ubuntu
linux-gke (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-64239

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-gke (Ubuntu package) - addressed in versions 6.8.0-146.146.1~22.04.1, 6.8.0-146.146.1, 6.8.0-1051.55, 6.8.0-1063.66, 6.8.0-1064.67~22.04.1, 6.8.0-1064.67, 6.8.0-1064.67.1, 6.8.0-1065.73, 6.8.0-1066.67
linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1036.39+1
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1068.75~22.04.1, 6.8.0-1068.75, 6.8.0-1069.77+fips1, 6.8.0-1070.78~22.04.1, 6.8.0-1070.78
linux-gcp (Ubuntu package) - update to 6.8.0-1070.78
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1016.16
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

External References

Related Security Bulletins