An exploitable regular expression without anchors vulnerability exists in the Web-Based Management (WBM) authentication functionality of WAGO PFC200 versions 03.00.39(12) and 03.01.07(13), and WAGO PFC100 version 03.00.39(12). A specially crafted authentication request can bypass regular expression filters, resulting in sensitive information disclosure.
https://talosintelligence.com/vulnerability_reports/TALOS-2019-0923