What’s Vulnerable › Vulnerabilities

CVE-2026-55836: Open Zaak: Path traversal / arbitrary server-file read via Documenten API document import (bestandspad)

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% 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-200

Description

Open Zaak is an open-source data and services layer for Dutch case-oriented working. From 1.13.0 until 1.27.2, 1.28.2, and 1.29.0, _import_document_row in src/openzaak/components/documenten/tasks.py uses the attacker-controlled bestandspad CSV field without ensuring that the resolved path remains under IMPORT_DOCUMENTEN_BASE_DIR. A client with an all-authorizations application token can supply an absolute or parent-traversal path to a file readable by the Celery service account. The worker copies that file into document storage, allowing its contents to be retrieved through the normal document download API and exposing server secrets or other private files. This issue is fixed in versions 1.27.2, 1.28.2, and 1.29.0.

Affected products

• open-zaak: from 1.13.0, < 1.27.2; from 1.28.0, < 1.28.2

References

• https://github.com/open-zaak/open-zaak/commit/4b23957b55ab792bc2ba1fbc5ce6918881b62ab8
• https://github.com/open-zaak/open-zaak/commit/69c78ce2a0edb45bec8809bc2205585c5f8a4054
• https://github.com/open-zaak/open-zaak/commit/8acd5e59e0132aa19284bf22f7b3defca279e2ce
• 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-x5cj-23hr-5r54
• https://github.com/open-zaak/open-zaak/security/advisories/GHSA-x5cj-23hr-5r54

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