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 identity-document verification admin UI embeds verification_attachment blobs through reusable signed Active Storage disk URLs, allowing anyone who obtains a URL to download the scanned document without an authenticated Decidim session until the signature expires. Verification-document images are rendered with variant_url(...), which produces signed /rails/active_storage/disk/... links instead of routing the file through an authorization-checking controller.
Because Decidim configures Active Storage service URLs to remain valid for seven days, the URL itself becomes the credential for that period. The affected files are verification_attachment blobs on Decidim::Authorization, and the admin review pages embed those signed URLs directly into the HTML for pending and confirmation views. This issue is fixed in versions 0.30.9, 0.31.5, and 0.32.0.rc2.
Attack Parameters
Impact Assessment
CVSS Vector v3.1