Horizon Alert
Summary of the vulnerability and why it matters
This vulnerability in Concrete CMS allows an authenticated administrator to include arbitrary files from the server. If combined with the ability to upload files with specific extensions that allow code execution, this could lead to remote code execution on the server.
- Administrators can gain server access.
- Affects systems allowing custom form layouts.
- Allows full server control.
Attack Path
How an attacker could exploit the issue
An attacker with administrative privileges and the ability to edit form layouts can exploit a path traversal flaw in Concrete CMS to read sensitive server files. If they can also upload files with executable content disguised as images, they can achieve remote code execution by tricking the application into processing the uploaded PHP code.
- Requires authenticated administrator access.
- Targets form layout composition.
- Needs file upload with extension bypass.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability allows an authenticated administrator to include arbitrary readable files on the server and potentially achieve remote code execution by leveraging a weak file upload validation. While not yet actively exploited in the wild, the potential for significant impact on internet-facing web applications makes it a compelling target. Attackers generally favor vulnerabilities in widely deployed web applications with accessible administrative interfaces.
- Exploitation is unconfirmed.
- No public exploits are available.
- The vulnerability is recently disclosed.
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
Focus on reviewing Concrete CMS logs for signs of unauthorized file access or remote code execution, and identify all instances of affected versions. Since this is a critical vulnerability with a high CVSS score and a known exploit path, prioritize isolating or taking affected services offline immediately if they are internet-facing.
- Block malicious traffic patterns.
- Isolate affected services immediately.
- Apply patch Concrete CMS 9.5.1 or later.
