CVE-2026-66915 in Fabrik Extension
Summary
by MITRE • 08/10/2026
Joomla Extension - fabrikar.com - Remote code execution in Fabrik < 4.6.7 - An unauthenticated attacker could execute arbitrary code by using the ajax_calc feature of the calc plugin.
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability identified in Fabrik versions prior to 4.6.7 represents a critical remote code execution flaw that directly impacts Joomla extension security. This issue resides within the ajax_calc feature of the calc plugin, which processes user-supplied data without adequate input validation or sanitization mechanisms. The vulnerability enables unauthenticated attackers to execute arbitrary code on affected systems, potentially leading to complete system compromise and unauthorized access to sensitive data.
The technical nature of this flaw stems from insufficient parameter validation within the calc plugin's ajax_calc functionality. When processing calculations through the web interface, the system fails to properly sanitize user inputs that are then passed to underlying execution functions. This creates a classic path for code injection attacks where malicious payloads can be executed with the privileges of the web server process. The vulnerability aligns with CWE-94, which describes improper control of generation of code, and represents a failure in input validation that allows arbitrary code execution.
From an operational perspective, this vulnerability poses significant risk to Joomla installations using the Fabrik extension. Attackers can exploit this weakness without requiring authentication credentials, making it particularly dangerous as it can be leveraged by anyone with access to the affected website. The impact extends beyond simple data theft to potential system takeover, allowing attackers to install backdoors, exfiltrate sensitive information, or deploy additional malware. This vulnerability directly maps to ATT&CK technique T1059.007 for command and scripting interpreter, specifically targeting web shell execution through remote code injection.
The exploitation of this vulnerability requires minimal prerequisites, as no authentication is needed to trigger the malicious code execution path. The affected systems typically include various versions of Joomla CMS with Fabrik extensions installed, particularly those running versions before 4.6.7. Organizations using these vulnerable versions face immediate risk of compromise, especially if their web applications are accessible from the internet.
Security mitigations for this vulnerability require prompt patching to version 4.6.7 or later, which includes proper input validation and sanitization measures in the calc plugin's ajax_calc feature. System administrators should also implement network-level protections such as web application firewalls that can detect and block suspicious payloads targeting known vulnerable endpoints. Additionally, monitoring for unusual execution patterns and implementing strict input validation policies for all user-supplied data can help reduce the attack surface. Organizations should conduct comprehensive vulnerability assessments to identify other potentially affected components within their Joomla installations and ensure proper security configurations are in place to prevent exploitation of similar weaknesses.