CVE-2018-7600, also known as "Drupalgeddon 2," identifies a critical remote code execution vulnerability in Drupal Core that enables unauthenticated attackers to execute arbitrary code through improper input validation in the Form API and rendering system. This vulnerability affects Drupal versions before 7.58, 8.x before 8.3.9, 8.4.x before 8.4.6, and 8.5.x before 8.5.1, achieving a maximum CVSS score of 9.8 (Critical severity) with an EPSS score of 100 percentile and 94.5% exploitation probability, indicating universal attack potential and widespread exploitation in the wild. The vulnerability details reveal that attackers can inject malicious array keys beginning with '#' (such as #post_render and #lazy_builder) through user-controlled parameters in forms like registration pages, bypassing input validation to trigger callback execution without proper authorization. This creates substantial exploit risk for Drupal websites and content management systems, particularly affecting default configurations and common module setups where Form API processing occurs without adequate input sanitization, making virtually all vulnerable Drupal installations susceptible to remote compromise. The technical root cause lies in Drupal's FormBuilder::doBuildForm and Renderer::renderRoot functions, which process user-supplied array keys without proper validation, allowing attackers to inject dangerous rendering callbacks that execute arbitrary PHP code, classified as CWE-20 (Improper Input Validation), creating a vector for known exploited vulnerabilities targeting content management systems. The vulnerability specifically exploits the absence of RequestSanitizer::stripDangerousValues in vulnerable versions, where AJAX callbacks and element processing can be manipulated to trigger rendering of malicious arrays containing executable code paths. With public exploits available, CISA KEV inclusion, and affecting PHP applications across multiple technologies, this vulnerability represents one of the most severe CMS security flaws due to its ease of exploitation and widespread Drupal deployment. Mitigation strategies require immediate upgrading to patched Drupal versions 7.58, 8.3.9, 8.4.6, or 8.5.1 and later, which implement proper input sanitization through RequestSanitizer to strip dangerous array keys and prevent callback injection attacks. Organizations should prioritize identifying all Drupal installations in their environment, apply emergency patches immediately due to active exploitation, implement web application firewalls to block malicious form submissions, monitor for indicators of compromise including unexpected file modifications or unauthorized code execution, and maintain updated CVE database records to track similar input validation vulnerabilities that could compromise content management security through unsafe form processing and rendering system exploitation in web applications.