Activesupport Project : Security Vulnerabilities, CVEs,

A regular expression based DoS vulnerability in Active Support <6.1.7.1 and <7.0.4.1. A specially crafted string passed to the underscore method can cause the regular expression engine to enter a state of catastrophic backtracking. This can cause the process to use large amounts of CPU and memory, leading to a possible DoS vulnerability.

active-support ruby gem 5.2.0 could allow a remote attacker to execute arbitrary code on the system, caused by containing a malicious backdoor. An attacker could exploit this vulnerability to execute arbitrary code on the system.