VDB-350444 · CVE-2026-28803 · GHSA-2g49-rfm6-5qj5

open-formulieren open-forms up to 3.3.12/3.4.4 access control

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.3	$0-$5k	0.00

Summaryinfo

A vulnerability labeled as critical has been found in open-formulieren open-forms up to 3.3.12/3.4.4. The affected element is an unknown function. Such manipulation leads to access control. This vulnerability is traded as CVE-2026-28803. The attack may be launched remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, has been found in open-formulieren open-forms up to 3.3.12/3.4.4. Affected by this issue is an unknown part. The manipulation with an unknown input leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Impacted is confidentiality. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-28803 since 03/03/2026. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1068.

Upgrading to version 3.3.13 or 3.4.5 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

open-formulieren

Name

open-forms

Version

Website

Product: https://github.com/open-formulieren/open-forms/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: open-forms 3.3.13/3.4.5

Timelineinfo

03/03/2026 CVE reserved
03/11/2026 +8 days Advisory disclosed
03/11/2026 +0 days VulDB entry created
03/14/2026 +3 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-2g49-rfm6-5qj5
Status: Confirmed

CVE: CVE-2026-28803 (🔒)
GCVE (CVE): GCVE-0-2026-28803
GCVE (VulDB): GCVE-100-350444

Entryinfo

Created: 03/11/2026 17:34
Updated: 03/14/2026 12:43
Changes: 03/11/2026 17:34 (65), 03/14/2026 12:43 (1)
Complete: 🔍
Cache ID: 216::103