What’s Vulnerable › Vulnerabilities

CVE-2026-54657: Open Zaak: /zaken/_zoek and /enkelvoudiginformatieobjecten/_zoek endpoints do not filter result lists based on authorizations linked to token

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-16 · updated 2026-10-16
• Weakness: CWE-285

Description

Open Zaak is an open-source data and services layer for Dutch case-oriented working. From 1.0.0 until 1.27.2, 1.28.2, and 1.29.0, the POST search endpoints /zaken/api/v1/zaken/_zoek and /documenten/api/v1/enkelvoudiginformatieobjecten/_zoek do not filter result querysets according to the authorizations associated with the request token. A caller with a valid zaken.lezen or documenten.lezen token can therefore retrieve case or document metadata outside the token's authorized types or confidentiality levels. Document searches require known UUIDs, and document content remains protected by separate download authorization. This issue is fixed in versions 1.27.2, 1.28.2, and 1.29.0.

Affected products

• open-zaak: from 1.0.0, < 1.27.2; from 1.28.0, < 1.28.2

References

• https://github.com/open-zaak/open-zaak/commit/15456f1a0ef4b0abf1b1c0e3a16c99c15423b9fd
• https://github.com/open-zaak/open-zaak/commit/4b429d3243d1532f6fe731f932a201cf0ddc4c18
• https://github.com/open-zaak/open-zaak/commit/d3869af98c60570782f867bab3e1d14fd8d8330f
• https://github.com/open-zaak/open-zaak/releases/tag/1.27.2
• https://github.com/open-zaak/open-zaak/releases/tag/1.28.2
• https://github.com/open-zaak/open-zaak/releases/tag/1.29.0
• https://github.com/open-zaak/open-zaak/security/advisories/GHSA-f29q-7rpr-jmjx

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