In uBlock before 0.9.5.15, the $rewrite filter option allows filter-list maintainers to run arbitrary code in a client-side session when a …

In uBlock before 0.9.5.15, the $rewrite filter option allows filter-list maintainers to run arbitrary code in a client-side session when a web service loads a script for execution using XMLHttpRequest or Fetch, and the script origin has an open redirect.