STIGQter: STIG Summary: Red Hat Enterprise Linux 8 Security Technical Implementation Guide Version: 2 Release: 8 Benchmark Date: 01 Jul 2026:

RHEL 8 must disable the use of user namespaces.

DISA Rule

SV-230548r1017310_rule

Vulnerability Number

V-230548

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

RHEL-08-040284

Severity

CAT II

CCI(s)

CCI-000366 - Implement the security configuration settings.

Weight

Fix Recommendation

Configure RHEL 8 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

Remove any configurations that conflict with the above from the following locations:
/run/sysctl.d/*.conf
/usr/local/lib/sysctl.d/*.conf
/usr/lib/sysctl.d/*.conf
/lib/sysctl.d/*.conf
/etc/sysctl.conf
/etc/sysctl.d/*.conf

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

Verify RHEL 8 disables the use of user namespaces with the following commands:

$ sudo 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 network parameter.

$ sudo grep -r user.max_user_namespaces /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf

/etc/sysctl.d/99-sysctl.conf: user.max_user_namespaces = 0

If "user.max_user_namespaces" is not set to "0", is missing or commented out, this is a finding.

If conflicting results are returned, this is a finding.

If the use of namespaces is operationally required and documented with the ISSM, it is not a finding.

Vulnerability Number

V-230548

Documentable

False

Rule Version

RHEL-08-040284

Severity Override Guidance

Check Content Reference

Target Key

2921