Describe CVE-2021-39938.
What is CVE-2021-39938?
A vulnerable regular expression pattern in GitLab CE/EE since version 8.15 before 14.3.6, all versions starting from 14.4 before 14.4.4, all versions starting from 14.5 before 14.5.2, allows an attacker to cause uncontrolled resource consumption leading to Denial of Service via specially crafted deploy Slash commands.