The Events Calendar <= 6.15.9 - Sysinfo Key Incorrect Comparison to Unauthenticated Sensitive Information Exposure

The Events Calendar plugin for WordPress is vulnerable to information disclosure in versions up to, and including, 6.15.9. The sysinfo REST endpoint compares the provided key to the stored opt-in key using a loose comparison, allowing unauthenticated attackers to send a boolean value and obtain the full system report whenever "Yes, automatically share my system information with The Events Calendar support team" setting is enabled.