infonl dimpact-zaakafhandelcomponent up to 5.1.x By-Id Read Endpoints ZaakRestService.kt improper authorization

Summaryinfo

A vulnerability was found in infonl dimpact-zaakafhandelcomponent up to 5.1.x. It has been rated as problematic. This affects the function listBesluitenForZaakUUID/listBesluitHistorie/downloadProcessDiagram/listAfzendersVoorZaak of the file src/main/kotlin/nl/info/zac/app/zaak/ZaakRestService.kt of the component By-Id Read Endpoints. The manipulation leads to improper authorization. This vulnerability is listed as CVE-2026-55551. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in infonl dimpact-zaakafhandelcomponent up to 5.1.x and classified as problematic. This issue affects the function listBesluitenForZaakUUID/listBesluitHistorie/downloadProcessDiagram/listAfzendersVoorZaak of the file src/main/kotlin/nl/info/zac/app/zaak/ZaakRestService.kt of the component By-Id Read Endpoints. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-55551 since 06/17/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1548.002 for this issue.

Upgrading to version 5.2.0 eliminates this vulnerability.

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Productinfo

Vendor

• infonl

Name

• dimpact-zaakafhandelcomponent

Version

• 5.0
• 5.1

Website

• Product: https://github.com/infonl/dimpact-zaakafhandelcomponent/

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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