CVE-2026-57995: phpMyFAQ Privilege Escalation Vulnerability

CVE-2026-57995 Overview

CVE-2026-57995 is a privilege escalation vulnerability [CWE-269] in phpMyFAQ versions before 4.1.5. The flaw exists in the GroupController::updatePermissions method, which fails to verify that the calling administrator holds the rights being assigned. Any user with the GROUP_EDIT permission can grant arbitrary rights to a group they belong to, inheriting elevated privileges through group membership. This enables a delegated administrator to escalate up to full administrative control of the phpMyFAQ instance.

Critical Impact
A low-privileged administrator with GROUP_EDIT rights can escalate to full administrative control by assigning high-value permissions to a group they belong to.

Affected Products

phpMyFAQ versions prior to 4.1.5
Self-hosted phpMyFAQ deployments with delegated group administration
Multi-tenant phpMyFAQ instances relying on role separation

Discovery Timeline

2026-06-30 - CVE-2026-57995 published to NVD
2026-07-02 - Last updated in NVD database

Technical Details for CVE-2026-57995

Vulnerability Analysis

The vulnerability resides in the GroupController::updatePermissions endpoint of phpMyFAQ. The controller processes permission updates submitted by administrators who hold the GROUP_EDIT right. However, it does not validate whether the calling user actually possesses the rights being applied to the target group.

This missing self-rights constraint breaks the delegated administration model. In a correctly designed system, an administrator can only grant permissions that they themselves already hold. phpMyFAQ instead grants any right that appears in the request payload, enabling vertical privilege escalation through group membership inheritance.

Since phpMyFAQ users inherit rights from every group they belong to, an attacker who edits a group they belong to immediately gains any permission assigned. The classification maps to CWE-269 (Improper Privilege Management).

Root Cause

The root cause is the absence of an authorization check comparing the acting administrator's effective rights against the rights being written by updatePermissions. The controller trusts that possession of GROUP_EDIT implies authority over all group-assignable rights, which is not the intended trust boundary.

Attack Vector

Exploitation requires network access to the phpMyFAQ web interface and an authenticated account with the GROUP_EDIT permission. No user interaction is required from other administrators. The attacker submits a permissions update for a group they belong to, adding high-value rights such as user administration, configuration management, or content approval. On the next session refresh, the attacker inherits those rights and can pivot to full administrative control.

The vulnerability manifests in the GroupController::updatePermissions handler. Refer to the GitHub Security Advisory GHSA-pg62-f8g4-4wqh and the VulnCheck Privilege Escalation Advisory for full technical details.

Detection Methods for CVE-2026-57995

Indicators of Compromise

Unexpected additions of high-privilege rights (for example, user or configuration administration) to groups via the phpMyFAQ admin backend.
HTTP POST or PUT requests to the group permissions update endpoint originating from accounts that hold only GROUP_EDIT rights.
Audit log entries showing group membership changes followed by permission changes on the same group within a short window.
Sudden expansion of effective rights for standard user accounts without corresponding role assignment events.

Detection Strategies

Review phpMyFAQ administrative audit logs for updatePermissions calls issued by non-superadmin accounts.
Compare each acting administrator's rights against the rights they assigned in group permission changes; any delta indicates possible abuse.
Alert on privilege changes to groups whose members include recently created or low-tier administrator accounts.

Monitoring Recommendations

Forward phpMyFAQ web server access logs and application audit logs to a centralized logging platform for correlation.
Baseline normal administrator behavior and alert on out-of-pattern permission mutations.
Monitor authentication events for administrators who gain new capabilities without a role reassignment.

How to Mitigate CVE-2026-57995

Immediate Actions Required

Upgrade phpMyFAQ to version 4.1.5 or later on all instances.
Audit every group's permission set and revoke rights that were not authorized by a superadministrator.
Review the list of accounts holding the GROUP_EDIT right and remove it from any account that does not require it.
Rotate credentials for administrator accounts if unauthorized privilege changes are detected.

Patch Information

The issue is fixed in phpMyFAQ 4.1.5. The patch introduces a self-rights constraint in GroupController::updatePermissions, ensuring administrators can only assign rights they themselves hold. See the GitHub Security Advisory GHSA-pg62-f8g4-4wqh for the fix commit and release notes.

Workarounds

Restrict the GROUP_EDIT right to fully trusted superadministrators until the upgrade is applied.
Place the phpMyFAQ admin backend behind network access controls such as VPN or IP allowlists to limit exposure.
Enable enhanced audit logging and manually review group permission changes daily until patched.

bash

# Upgrade phpMyFAQ to the fixed release
cd /var/www/phpmyfaq
php composer.phar require thorsten/phpmyfaq:^4.1.5

# Temporary hardening: restrict admin backend by source IP (nginx example)
# location /admin/ {
#     allow 10.0.0.0/24;
#     deny all;
# }