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CVE-2020-26251

MediumCVSS 4.7 / 10
Published Dec 18, 2020·Last modified Apr 10, 2026
Affected Components(0)

No affected components available

Description

Open Zaak is a modern, open-source data- and services-layer to enable zaakgericht werken, a Dutch approach to case management. In Open Zaak before version 1.3.3 the Cross-Origin-Resource-Sharing policy in Open Zaak is currently wide open - every client is allowed. This allows evil.com to run scripts that perform AJAX calls to known Open Zaak installations, and the browser will not block these. This was intended to only apply to development machines running on localhost/127.0.0.1. Open Zaak 1.3.3 disables CORS by default, while it can be opted-in through environment variables. The vulnerability does not actually seem exploitable because: a) The session cookie has a Same-Site: Lax policy which prevents it from being sent along in Cross-Origin requests. b) All pages that give access to (production) data are login-protected c) Access-Control-Allow-Credentials is set to false d) CSRF checks probably block the remote origin, since they're not explicitly added to the trusted allowlist.

Risk Scores
Base Score
4.7

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a low impact on the confidentiality of the information. There is a low impact on the integrity of the data.

Threat Intelligence
4.3

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.45%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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