Decidim: Admin user search allows SQL injection through similarity-based sorting

Decidim is a participatory democracy framework. Prior to 0.30.9, from 0.31.0 before 0.31.5, and in 0.32.0.rc1 before 0.32.0.rc2, the GET /admin/organization/users search interpolates params[:term] into raw Arel.sql ORDER BY similarity expressions before sanitization, allowing an authenticated organization administrator to execute blind PostgreSQL expressions and infer data through timing differences. This issue is fixed in versions 0.30.9, 0.31.5, and 0.32.0.rc2.