Information disclosure in Open-Zaak
CVE-2026-55836
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.
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Open-Zaak — versions >= 1.13.0, < 1.27.2, >= 1.28.0, < 1.28.2
Weakness classification (CWE)
References
- github.com/open-zaak/open-zaak/security/advisories/GHSA-x5cj-23hr-5r54
- github.com/open-zaak/open-zaak/commit/4b23957b55ab792bc2ba1fbc5ce6918881b62ab8
- github.com/open-zaak/open-zaak/commit/69c78ce2a0edb45bec8809bc2205585c5f8a4054
- github.com/open-zaak/open-zaak/commit/8acd5e59e0132aa19284bf22f7b3defca279e2ce
- github.com/open-zaak/open-zaak/releases/tag/1.27.2
- github.com/open-zaak/open-zaak/releases/tag/1.28.2
- github.com/open-zaak/open-zaak/releases/tag/1.29.0
Frequently asked questions
- What is CVE-2026-55836?
- CVE-2026-55836 is a medium-severity vulnerability in Open-Zaak, classified under Information Disclosure. CVSS score: 6.8/10. Published 2026-10-16.
- How severe is CVE-2026-55836?
- Medium severity. CVSS v3 base score is 6.8 out of 10.