Phalcon is a high-performance, full-stack PHP framework. Prior to 5.15.0, every Phalcon MVC application built with a default router register

Phalcon is a high-performance, full-stack PHP framework. Prior to 5.15.0, every Phalcon MVC application built with a default router registers a built-in route whose compiled PCRE pattern contains the nested quantifier (/.), and the same construct is produced by the /:params placeholder and the CLI router. Phalcon\Mvc\Router::handle() matches this pattern against the attacker-controlled request URI on every request, so a crafted path such as one containing repeated slashes followed by decoded newlines can trigger catastrophic backtracking and cause CPU exhaustion or route-matching failure. This issue is fixed in version 5.15.0.