This advisory discloses a critical severity security vulnerability which was introduced in version 1.4.1 of Crowd. Versions of Crowd starting with 1.4.1 before 2.8.8 (the fixed version for 2.8.x) and from 2.9.0 before 2.9.5 (the fixed version for 2.9.x) are affected by this vulnerability. The Crowd LDAP directory connector allowed an attacker to gain remote code execution in Crowd by injecting malicious attributes in LDAP entries.