Use-after-free in Linux kernel - CVE-2026-64142

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Main Vulnerability Database Vulnerabilities #VU138479

Use-after-free in Linux kernel - CVE-2026-64142

Published: July 20, 2026


Vulnerability identifier: #VU138479
CSH Severity: Medium
CVSS v4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-64142
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote user to cause a denial of service and potentially execute arbitrary code.

The vulnerability exists due to use-after-free in ksmbd durable handle management and m_fp_list walkers when processing concurrent durable-handle expiration and file lookup operations. A remote user can trigger concurrent durable handle expiration and lookup activity to cause a denial of service and potentially execute arbitrary code.

The issue involves a race between the durable scavenger and walkers such as ksmbd_lookup_fd_inode() and share-mode checks, and exploitation requires access to SMB operations that exercise durable handles.


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-2026-64142

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