CVE-2026-28803 | BDVDB-2026-319975 Detail

open-formulierenopen-forms

Description#

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.

Impact#

Per CVSS v3.1: confidentiality impact high, integrity impact none, availability impact none. Attack vector: network.

Weaknesses#

CWE-284 Improper Access Control

References#

https://github.com/open-formulieren/open-forms/security/advisories/GHSA-2g49-rfm6-5qj5

Exploit#

No public exploit known

History#

Version 12026-03-11Record published in the CVE List.

Published

Published: 2026-03-11
Last modified: 2026-03-11

Vendor information

Vendor: open-formulieren
Product: open-forms

All open-formulieren vulnerabilities

Score

6.5 Medium

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 14.3.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Improper Access Control

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
>= 3.4.0-alpha.0, < 3.4.5
Fixed
Not stated
Vulnerable
< 3.3.13
Fixed
Not stated

Scoring System

CVSS v4.0

Not available

CVSS v3.1

6.5 Medium

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	Low
User Interaction	None
Scope	Unchanged
Confidentiality	High
Integrity	None
Availability	None

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).