A flaw was found in Kroxylicious. The ACL authorizer's rules-file parser unquotes "matching /…/" regular-expression literals using the string unquoting rules, which strips every backslash escape. As a result, an allow rule such as "matching /orders\.v1/" is compiled as the regex "orders.v1", which also matches unintended names such as "ordersXv1", and character classes such as "\d" and "\w" lose their special meaning. Allow rules written with regex escapes can therefore apply to more resources than the author intended. Depending on the ACL configuration, this may allow an authenticated Kafka client to access a resource (such as read or write a topic) that should have been denied.