Improper access control in Linux kernel - CVE-2026-64137

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Main Vulnerability Database Vulnerabilities #VU138500

Improper access control in Linux kernel - CVE-2026-64137

Published: July 20, 2026


Vulnerability identifier: #VU138500
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-64137
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to improper access control in the CIFS SWN generic netlink multicast group when joining the multicast group and receiving registration messages. A local user can join the CIFS_GENL_MCGRP_SWN group to disclose sensitive information.

For NTLM-authenticated mounts, exposed registration messages may include the username, domain, and password attributes copied from the CIFS session.


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-2026-64137

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