CVE-2026-55836 Open Zaak: Path traversal / arbitrary server-file read via Documenten API document import (bestandspad)
An attacker with an application token can use path traversal in the document import API to read arbitrary server files via the Celery worker.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-55836?
CVE-2026-55836 is a medium-severity path traversal vulnerability in open-zaak, published on 16 Oct 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official 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.
Weakness: CWE-200
Which versions are affected by CVE-2026-55836?
How do I fix CVE-2026-55836?
No fix has been published for CVE-2026-55836 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-55836 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55836 exists.
Sources
Also known as GHSA-x5cj-23hr-5r54.