CVE-2026-55551
ZAC is an open-source, workflow-based Common Ground component for Dutch municipal case management. Prior to 5.2.0, by-id read endpoints in `
CVSS
6.5
Medium
EPSS
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KEV
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Exploit Today
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0-100
Published: Oct 30, 2026 · Last modified: Oct 30, 2026 · CWE-285 · CWE-639
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ZAC is an open-source, workflow-based Common Ground component for Dutch municipal case management. Prior to 5.2.0, by-id read endpoints in `src/main/kotlin/nl/info/zac/app/zaak/ZaakRestService.kt` omit `assertPolicy`(`policyService.readZaakRechten(zaak).lezen`) authorization. `RequestAuthorizationFilter` and `hasAnyApplicationRole` require only an application role on any zaaktype, not the target case's type, while `zaak-rechten.rego` enforces the actual `zaaktype_allowed` boundary only when invoked. An authenticated low-privileged municipal user who knows a case or decision UUID can use `GET /rest/zaken/besluit/zaakUuid/{uuid}` (`listBesluitenForZaakUUID`) to read decisions including types, dates, and free-text toelichting; `GET /rest/zaken/besluit/{uuid}/historie` (`listBesluitHistorie`) to read audit old/new values; and `GET /rest/zaken/{uuid}/process-diagram` (`downloadProcessDiagram`) to read BPMN workflow state across unauthorized zaaktypes. The advisory also identifies `zaak/{uuid}/afzender` (`listAfzendersVoorZaak`) as exposing zaaktype mailbox configuration without a policy check. The search/_zoek path is correctly authorization-filtered and is not part of this by-id read cluster. This issue is fixed in version 5.2.0.
- github.comhttps://github.com/infonl/dimpact-zaakafhandelcomponent/commit/7b90586be658cec9fa5c98c0838636237f40931f
- github.comhttps://github.com/infonl/dimpact-zaakafhandelcomponent/commit/d050f247301a1bcfb867015725a693c540a06f5a
- github.comhttps://github.com/infonl/dimpact-zaakafhandelcomponent/pull/6225
- github.comhttps://github.com/infonl/dimpact-zaakafhandelcomponent/pull/6229
- github.comhttps://github.com/infonl/dimpact-zaakafhandelcomponent/releases/tag/v5.2.0
- github.comhttps://github.com/infonl/dimpact-zaakafhandelcomponent/security/advisories/GHSA-cv9m-35q4-cxfm