CVE-2026-111893 in phpMyFAQ
Summary
by MITRE • 10/17/2026
phpMyFAQ 4.2.0-alpha before 4.2.0-beta contains a privilege escalation vulnerability in GroupController::saveCategoryRestrictions() that lets delegated administrators assign categories outside their own scope. Category-restricted administrators can POST to /admin/api/group/category-restrictions with out-of-scope or empty categoryIds to grant groups unrestricted category access.
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Analysis
by VulDB Data Team • 10/18/2026
The identified security flaw resides within the phpMyFAQ content management system, specifically affecting versions prior to 4.2.0-beta in the GroupController component. This vulnerability represents a critical failure in server-side authorization logic, allowing delegated administrators with restricted permissions to bypass intended scope limitations. The core technical issue is located in the saveCategoryRestrictions method, which handles HTTP POST requests directed at the /admin/api/group/category-restrictions endpoint. In a properly secured implementation, this function should validate that any category identifiers provided by the requesting user fall strictly within the boundaries of their assigned administrative privileges. However, due to insufficient input validation and lack of rigorous access control checks, the application fails to enforce these constraints effectively.
An attacker possessing delegated administrator rights can exploit this flaw by crafting a malicious POST request containing either empty arrays for categoryIds or lists of identifiers corresponding to categories outside their designated scope. By submitting such data, the system erroneously interprets these inputs as valid configuration updates and proceeds to modify group permissions accordingly. This mechanism allows the attacker to elevate privileges from a restricted role to one with unrestricted access across all knowledge base categories. The vulnerability stems directly from improper implementation of access control mechanisms where the server trusts client-supplied identifiers without verifying them against the user's actual permission set stored in the backend database or session state.
The operational impact of this privilege escalation is severe, as it compromises the integrity and confidentiality of the entire content management system. Once an attacker gains unrestricted category access, they can view, edit, delete, or publish any article regardless of its sensitivity level. This undermines the fundamental principle of least privilege that organizations rely on to segment administrative duties among multiple users. In enterprise environments where phpMyFAQ is used for internal documentation or customer support knowledge bases, this could lead to unauthorized disclosure of proprietary information, manipulation of public-facing content, and potential further exploitation through stored cross-site scripting if malicious scripts are embedded in articles by the now-elevated attacker account.
From a classification perspective, this vulnerability aligns with CWE-269 Improper Privilege Management, specifically illustrating how inadequate enforcement of role-based access controls can lead to privilege escalation. It also maps closely to MITRE ATT&CK technique T1078 Valid Accounts, where an adversary uses legitimate credentials but exploits configuration weaknesses to gain higher-level permissions than intended. The attack vector is classified as remote with low complexity since it requires only a single crafted HTTP request and does not necessitate complex exploitation chains or physical access.
To mitigate this vulnerability, organizations must immediately upgrade phpMyFAQ to version 4.2.0-beta or later where the issue has been addressed in subsequent releases. For environments unable to patch instantly due to compatibility constraints, temporary mitigation strategies should include restricting direct API endpoint exposure through web application firewalls that validate request payloads against expected parameter ranges and user roles. Additionally, implementing strict server-side validation logic that cross-references submitted category IDs with the requesting user's authorized scope before processing any permission changes is essential. Regular security audits focusing on authorization checks in administrative interfaces can help identify similar flaws across other modules of the application ensuring robust defense-in-depth practices are maintained throughout the system architecture.