CVE-2026-13544: Feehi CMS 2.1.1 API Access Control Flaw – Remediation Guide

Technical summary

CVE-2026-13544 is a privilege escalation vulnerability affecting the /api/users endpoint in Feehi CMS. The flaw stems from improper access control mechanisms (CWE-266: Improper Privilege Management, CWE-284: Improper Access Control by Frame ID) that fail to properly validate user permissions before allowing API operations. An authenticated attacker can manipulate requests to this endpoint to perform actions beyond their assigned role or access confidential user information. The vulnerability requires authentication (CVSS vector PR:L) but has low attack complexity and impacts confidentiality, integrity, and availability.

Business impact

Organizations deploying Feehi CMS as their content management platform face a direct user data protection risk. Attackers with any valid account—including low-privilege users—can escalate access to view, modify, or remove user records, potentially compromising customer databases, staff directories, or administrative credentials. The published exploit lowers the technical barrier for malicious actors and increases the likelihood of opportunistic attacks. Remediation delay is a critical concern, as the vendor has not yet confirmed receipt or response to the original report.

Affected systems

Feehi CMS versions 2.1.1 and earlier are confirmed affected. No information on patched versions is currently available from the vendor. Organizations should inventory all Feehi CMS deployments and determine their specific version number. The vulnerability applies regardless of deployment context (self-hosted, cloud-based, or containerized).

Exploitability

This vulnerability has a moderate CVSS score (6.3) but practical exploitability is relatively high due to published proof-of-concept code. Exploitation requires valid user credentials, which is a meaningful barrier in many environments but easily overcome if users reuse passwords or if weak account hygiene practices exist. The remote, network-accessible nature of the /api/users endpoint means attackers can attempt exploitation from anywhere without physical access or advanced tools.

Remediation

First, verify your Feehi CMS version by checking the admin panel or configuration files. If running version 2.1.1 or earlier, you are affected. Check the official Feehi CMS GitHub repository, changelog, or vendor website for available security patches—as of this report date, no patch has been released. If no patch is available, consider implementing network-level access controls to restrict API endpoint access to trusted IP ranges, or temporarily disable the /api/users endpoint if not critical to operations. Plan to upgrade immediately once a patched version is released by the vendor. Subscribe to the project's security notifications to receive patch notifications.

Patch guidance

No vendor patch is currently available. Feehi CMS maintainers have been notified but have not issued a security release. Monitor the official Feehi CMS repository releases page and security advisories closely. When a patch is published, verify the version number and release notes to confirm the CVE-2026-13544 fix is included before applying. Test patches in a non-production environment first to ensure compatibility with your configuration and plugins.

Detection guidance

Monitor API access logs for /api/users endpoint requests, particularly those originating from low-privilege user accounts or unusual source IP addresses. Look for repeated failed authentication attempts followed by successful API calls—a pattern often seen in credential enumeration attacks. Web application firewall (WAF) rules can flag suspicious API manipulation patterns. If you have database access, audit user creation, modification, and deletion timestamps for unexplained changes. Check for any unauthorized user accounts or privilege escalations in audit logs.

Why prioritize this

Although the CVSS score is moderate (6.3), this vulnerability warrants near-term action because: (1) a working exploit is publicly available, lowering attacker skill requirements; (2) it requires only authenticated access, not unusual given typical CMS user bases; (3) it directly affects user data confidentiality and integrity; and (4) no patch currently exists, forcing immediate defensive measures. If your Feehi CMS instance is internet-facing or processes sensitive user data, treat this as a high priority pending patch availability.

Risk score, explained

The CVSS 6.3 MEDIUM rating reflects the combination of low attack complexity, network accessibility, and low privilege requirement (positive factors for attackers), offset by the requirement for authentication and limited impact scope. However, the real-world risk is elevated by the existence of working exploit code and the lack of a vendor response, which extends the window of exposure and increases attack likelihood.

Frequently asked questions