{"cve":"CVE-2020-26251","nvd":{"published":"2020-12-18T18:15:12.543","modified":"2026-06-17T03:07:55.353","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N","score":4.7},"cwes":["CWE-346"],"references":["https://github.com/open-zaak/open-zaak/blob/master/CHANGELOG.rst#133-2020-12-17","https://github.com/open-zaak/open-zaak/commit/952269269f1b629fce9c94485f83ac13f31d6c46","https://github.com/open-zaak/open-zaak/security/advisories/GHSA-chhr-gxrg-64x7","https://github.com/open-zaak/open-zaak/blob/master/CHANGELOG.rst#133-2020-12-17","https://github.com/open-zaak/open-zaak/commit/952269269f1b629fce9c94485f83ac13f31d6c46"],"products":["openzaak:open_zaak"],"source":"nvd","synced_at":"2026-10-19T21:12:09.559580076+00:00"},"epss":{"cve":"CVE-2020-26251","score":0.00453,"percentile":0.39349,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}