---
id: CVE-2026-55551
title: 'ZAC: Missing per-zaaktype authorization on by-ID decision and process reads'
summary: >-
  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.readZ…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-285
  - CWE-639
vendor: infonl
product: dimpact-zaakafhandelcomponent
affected:
  - dimpact-zaakafhandelcomponent < 5.2.0
published: '2026-10-30'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T16:48:51.352Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-55551'
references:
  - url: >-
      https://github.com/infonl/dimpact-zaakafhandelcomponent/security/advisories/GHSA-cv9m-35q4-cxfm
    label: >-
      https://github.com/infonl/dimpact-zaakafhandelcomponent/security/advisories/GHSA-cv9m-35q4-cxfm
  - url: 'https://github.com/infonl/dimpact-zaakafhandelcomponent/pull/6225'
    label: 'https://github.com/infonl/dimpact-zaakafhandelcomponent/pull/6225'
  - url: 'https://github.com/infonl/dimpact-zaakafhandelcomponent/pull/6229'
    label: 'https://github.com/infonl/dimpact-zaakafhandelcomponent/pull/6229'
  - url: >-
      https://github.com/infonl/dimpact-zaakafhandelcomponent/commit/7b90586be658cec9fa5c98c0838636237f40931f
    label: >-
      https://github.com/infonl/dimpact-zaakafhandelcomponent/commit/7b90586be658cec9fa5c98c0838636237f40931f
  - url: >-
      https://github.com/infonl/dimpact-zaakafhandelcomponent/commit/d050f247301a1bcfb867015725a693c540a06f5a
    label: >-
      https://github.com/infonl/dimpact-zaakafhandelcomponent/commit/d050f247301a1bcfb867015725a693c540a06f5a
  - url: >-
      https://github.com/infonl/dimpact-zaakafhandelcomponent/releases/tag/v5.2.0
    label: >-
      https://github.com/infonl/dimpact-zaakafhandelcomponent/releases/tag/v5.2.0
tags:
  - cve.org
epss: 0.00257
epssPercentile: 0.17523
ingestedAt: '2026-11-05T16:24:31.090Z'
---

## Overview

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.

## Affected

- `dimpact-zaakafhandelcomponent < 5.2.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.