In Forgejo through 13.0.3, the attachment component allows a denial of service by uploading a multi-gigabyte file attachment (e.g., to be associated with an issue or a release).
Forgejo before 13.0.2 allows attackers to write to unintended files, and possibly obtain server shell access, because of mishandling of out-of-repository symlink destinations for template repositories. This is also fixed for 11 LTS in 11.0.7 and later.