October CMS: Environment Variable Exfiltration via INI Parser Interpolation

October is a Content Management System (CMS) and web platform. Versions prior to 3.7.14 and 4.1.10 contain a server-side information disclosure vulnerability in the INI settings parser. Because PHP's parse_ini_string() function supports ${} syntax for environment variable interpolation, attackers with Editor access could inject patterns such as ${APP_KEY} or ${DB_PASSWORD} into CMS page settings fields, causing sensitive environment variables to be resolved, stored in the template, and returned to the attacker when the page was reopened. This could enable exfiltration of credentials and secrets (database passwords, AWS keys, application keys), potentially leading to further attacks such as database access or cookie forgery. The vulnerability is only relevant when cms.safe_mode is enabled, as direct PHP injection is already possible otherwise. This issue has been fixed in versions 3.7.14 and 4.1.10. If users are unable to immediately upgrade, they can workaround this issue by restricting Editor tool access to fully trusted administrators only, and ensuring database and cloud service credentials are not accessible from the web server's network.