Improper Input Validation
An issue was discovered in the CasAuth extension for MediaWiki through 1.35.1. Due to improper username validation, it allowed user impersonation with trivial manipulations of certain characters within a given username. An ordinary user may be able to login as a "bureaucrat user" who has a similar username, as demonstrated by usernames that differ only in (1) bidirectional override symbols or (2) blank space.
CWE-20 - Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.