Wekan: ReDoS via Unescaped User Input in RegExp

Wekan is open source kanban built with Meteor. Prior to 11.11, the user-search publication in server/publications/users.js and the searchUsers method in server/models/users.js pass authenticated user-controlled searchTerm and query values to new RegExp() without escaping regular-expression metacharacters. MongoDB-backed deployments evaluate the resulting patterns with PCRE2, allowing a logged-in user to submit catastrophic-backtracking expressions that consume database CPU and degrade or deny service to other users; searchUsers additionally requires board membership or site-admin status. The FerretDB v1 / RE2 unaffected configuration is not practically affected by catastrophic backtracking. This issue is fixed in version 11.11.