Executive Summary

CVE-2026-35671 is an insecure direct object reference (IDOR) vulnerability in phpMyFAQ versions before 4.1.3, specifically in the admin API user password endpoint.

This flaw allows an authenticated administrator with low privileges to change any user's password without proper authorization verification by manipulating the userId parameter in the overwrite-password API request.

As a result, an attacker can escalate their privileges to SuperAdmin by modifying the userId parameter to target the SuperAdmin account.

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Impact Analysis

This vulnerability can have severe impacts including full system compromise.

• An attacker with low-privilege admin credentials can escalate to SuperAdmin privileges.
• The attacker can change any user's password, including SuperAdmin accounts, without authorization.
• This leads to high impacts on confidentiality, integrity, and availability of the system.
• Organizations with multiple admin users, privilege separation, or multi-tenant environments are particularly at risk.

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Detection Guidance

This vulnerability can be detected by monitoring API requests to the admin password overwrite endpoint for suspicious manipulation of the userId parameter.

Specifically, look for authenticated admin API requests where the userId parameter is changed to target users other than the requester's own account, especially userId=1 (SuperAdmin).

Commands to detect such activity could include inspecting web server logs or API gateway logs for POST requests to the overwrite-password endpoint with unusual userId values.

• Use grep or similar tools to search logs for the API endpoint, e.g., `grep 'overwrite-password' /var/log/nginx/access.log`
• Filter for requests containing userId parameters different from the authenticated admin's own ID.
• Monitor for CSRF tokens usage patterns or unexpected password change requests from low-privilege admin accounts.

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Mitigation Strategies

Immediate mitigation steps include upgrading phpMyFAQ to version 4.1.3 or later, where this vulnerability is fixed.

If upgrading is not immediately possible, restrict access to the admin API endpoints to trusted administrators only and monitor API usage closely.

Implement additional authorization checks or multi-factor authentication for password changes, especially for high-privilege accounts.

Review and limit the number of administrators with USER_EDIT permissions to reduce the attack surface.

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Compliance Impact

The vulnerability allows low-privilege administrators to escalate their privileges to SuperAdmin by changing any user's password without proper authorization checks. This can lead to unauthorized access to sensitive data and full system compromise.

Such unauthorized privilege escalation and potential data breaches can negatively impact compliance with common standards and regulations like GDPR and HIPAA, which require strict access controls and protection of sensitive information.

Organizations using affected versions of phpMyFAQ may face increased risk of violating these regulations due to improper privilege management and lack of authorization verification.

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