Open Forms allows users create and publish smart forms. Prior to 3.3.13 and 3.4.5, to be able to cosign, the cosigner receives an e-mail with instructions or a deep-link to start the cosign flow. The submission reference is communicated so that the user can retrieve the submission to be cosigned. Attackers can guess a code or modify the received code to look up arbitrary submissions, after logging in (with DigiD/eHerkenning/... depending on form configuration). This vulnerability is fixed in 3.3.13 and 3.4.5.
Exploitability
AV:NAC:LPR:LUI:NScope
S:UImpact
C:HI:NA:N6.5/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:NConfiguration