STIGQter: STIG Summary: Cloud Linux AlmaLinux OS 9 Security Technical Implementation Guide Version: 1 Release: 7 Benchmark Date: 01 Jul 2026:

AlmaLinux OS 9 must disable the use of user namespaces.

DISA Rule

SV-269284r1101813_rule

Vulnerability Number

V-269284

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

ALMA-09-023010

Severity

CAT II

CCI(s)

CCI-000366 - Implement the security configuration settings.

Weight

Fix Recommendation

Configure AlmaLinux OS 9 to disable the use of user namespaces by adding the following line to a file, in the "/etc/sysctl.d" directory:

user.max_user_namespaces = 0

The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command:

$ sudo sysctl --system

Check Contents

Note: User namespaces are used primarily for Linux containers. If containers are in use, this requirement is Not Applicable.

Verify AlmaLinux OS 9 disables the use of user namespaces with the following commands:

$ sysctl user.max_user_namespaces

user.max_user_namespaces = 0

If the returned line does not have a value of "0", or a line is not returned, this is a finding.

Check that the configuration files are present to enable this kernel parameter.

$ /usr/lib/systemd/systemd-sysctl --cat-config | egrep -v '^(#|;)' | grep -F user.max_user_namespaces | tail -1

user.max_user_namespaces = 0

If the network parameter "user.max_user_namespaces" is not equal to "0", or nothing is returned, this is a finding.

Vulnerability Number

V-269284

Documentable

False

Rule Version

ALMA-09-023010

Severity Override Guidance

Check Content Reference

Target Key

5664