The Moodle security vulnerability` refers to a critical issue discovered in the widely-used open-source e-Learning software, allowing attackers to execute arbitrary commands on the underlying operating system of a server running Moodle. The vulnerability is triggered by a math formula used in the Quiz component, which can be manipulated to bypass internal security mechanisms and inject malicious PHP code via the `eval()` function. The exploit takes advantage of the way Moodle validates formulas, specifically through the use of placeholder substitution and regular expression-based validation, allowing attackers to hide malicious characters from detection. Four patches were proposed by the Moodle team in response to the vulnerability, but each had its own limitations and bypasses, ultimately requiring further analysis and adaptation to fully secure the application. The vulnerability highlights the importance of automated security testing and collaboration between vendors and researchers to address critical issues in time.