STIGQter: STIG Summary: Mozilla Firefox Security Technical Implementation Guide Version: 6 Release: 8 Benchmark Date: 01 Jul 2026:

Firefox must be configured to disable the installation of extensions.

DISA Rule

SV-251557r960963_rule

Vulnerability Number

V-251557

Group Title

SRG-APP-000141

Rule Version

FFOX-00-000013

Severity

CAT II

CCI(s)

• CCI-000381 - Configure the system to provide only organization-defined mission essential capabilities.

Weight

10

Fix Recommendation

Windows group policy:
1. Open the group policy editor tool with "gpedit.msc".
2. Navigate to Policy Path: Computer Configuration\Administrative Templates\Mozilla\Firefox\Addons
Policy Name: Allow add-on installs from websites
Policy State: Disabled

macOS "plist" file:
Add the following:
<key>InstallAddonsPermission</key>
<false/>

Linux "policies.json" file:
Add the following in the policies section:
"InstallAddonsPermission": {
"Default": false
}

Check Contents

Type "about:policies" in the browser address bar.

If "InstallAddonsPermission" is not displayed under Policy Name or the Policy Value is not "Default" "false", this is a finding.

Vulnerability Number

V-251557

Documentable

False

Rule Version

FFOX-00-000013

Severity Override Guidance

Type "about:policies" in the browser address bar.

If "InstallAddonsPermission" is not displayed under Policy Name or the Policy Value is not "Default" "false", this is a finding.

Check Content Reference

M

Target Key

5446