Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, the default deny-lists used by Gotenberg's downloadFrom feature and webhook feature are bypassable. Because the filter is regex-based and case-sensitive, an unauthenticated attacker can supply URLs such as http://[::ffff:127.0.0.1]:... and reach loopback or private HTTP services that the default deny-list is intended to block. This crosses a real security boundary because an external caller can force the server to make outbound requests to internal-only targets. This vulnerability is fixed in 8.31.0.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:HI:HA:L9.4/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:LInput Validation