CVE-2026-28803
mediumpriority · track · 0EPSS 0.002 · 11 %ileEUUSEPSS · scored 2026-10-26
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (4)
Products and version ranges known to be affected.
also known as (2)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (4)
External citations — patches, advisories, analysis.
- https://github.com/open-formulieren/open-formsPatchcnnvd
- https://github.com/open-formulieren/open-forms/security/advisories/GHSA-2g49-rfm6-5qj5cnnvd
- https://github.com/open-formulieren/open-forms/security/advisories/GHSA-2g49-rfm6-5qj5enisa_euvd
- https://github.com/open-formulieren/open-forms/security/advisories/GHSA-2g49-rfm6-5qj5MitigationVendor Advisorynvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan