uBlock Origin before 1.36.2 and nMatrix before 4.4.9 support an arbitrary depth of parameter nesting for strict blocking, which allows crafted web sites to cause a denial of service (unbounded recursion that can trigger memory consumption and a loss of all blocking functionality).

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.