RHEL 9 must mount /dev/shm with the nosuid option.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-257865 | RHEL-09-231120 | SV-257865r1184297_rule | CCI-001764 | medium |
| Description | ||||
| The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for nonprivileged users to attain unauthorized administrative access. | ||||
| STIG | Date | |||
| Red Hat Enterprise Linux 9 Security Technical Implementation Guide | 2026-02-05 | |||
Details
Check Text (C-257865r1184297_chk)
Verify "/dev/shm" is mounted with the "nosuid" option with the following command:
$ findmnt /dev/shm
/dev/shm tmpfs tmpfs rw,nodev,nosuid,noexec,seclabel
If the mount options for /dev/shm does not include nosuid, this is a finding.
Fix Text (F-61530r1155635_fix)
Configure "/dev/shm" to mount with the "nosuid" option.
Modify "/etc/fstab" to use the "nosuid" option on the "/dev/shm" file system.
To reload all implicit mount units and update the dependency graph so that new options will apply correctly at next remount, run the following command:
$ sudo systemctl daemon-reload
Use the following command to apply the changes immediately without a reboot:
$ sudo mount -o remount /dev/shm