Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
GNU Mailman before 2.1.33 allows arbitrary content injection via the Cgi/private.py private archive login page.
CWE-74 - Injection
Listed as the number one web application security risk on the 'OWASP Top Ten', injection attacks are widespread and dangerous, especially in legacy applications. Injection attacks are a class of vulnerabilities in which an attacker injects untrusted data into a web application that gets processed by an interpreter, altering the program's execution. This can result in data loss/theft, loss of data integrity, denial of service, and even compromising the entire system.