REVA is an interoperability platform. Prior to 2.42.3 and 2.40.3, a bug in the GRPC authorization middleware of the "Reva" component of OpenCloud allows a malicious user to bypass the scope verification of a public link. By exploiting this via the the "archiver" service this can be leveraged to create an archive (zip or tar-file) containing all resources that this creator of the public link has access to. This vulnerability is fixed in 2.42.3 and 2.40.3.
https://github.com/opencloud-eu/reva/security/advisories/GHSA-9j2f-3rj3-wgpg
https://github.com/opencloud-eu/reva/commit/95aa2bc5d980eaf6cc134d75782b4f5ac7b36ae1