This article examines the human rights standards relevant to the use of upload filters for content moderation within EU secondary legislation. Upload filters, which automatically screen user-generated content before publication, are a type of prior restraint, which raises critical concerns on freedom of expression. EU secondary legislation establishes rules for both mandatory and voluntary use of these technologies, which must be read in light of human rights protections. This article analyses the characteristics of both mandatory and voluntary upload filters as prior restraints, the relevant EU legal provisions governing their use, and the safeguards required to prevent disproportionate restrictions on speech. Additionally, it explores the procedural and institutional safeguards under EU law, viewed through the lens of the CJEU and ECtHR case law on prior restraints and the rights to a fair trial and to an effective remedy.