{"id":"CVE-2026-55836","kind":"vulnerability","aliases":["CVE-2026-55836"],"related":[],"title":"Open Zaak: CSV import path lets authorized client read server files","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.","summary":"Open Zaak's document import task does not confine the bestandspad path in uploaded CSV rows to the configured import directory. A client with an all-authorizations application token can point it at any file the Celery worker can read, and the worker copies that file into document storage where it can be downloaded.","severity":"medium","cvss":6.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["celery","document-import","open-zaak","package","self-hosted"],"not_affected_if":["fixed-version","narrow-token-scopes","no-csv-document-import"],"how_to_check":"- Check the installed Open Zaak version and compare it to the fixed releases listed in the fix field.\n- Look for IMPORT_DOCUMENTEN_BASE_DIR in the deployment settings to confirm whether document CSV imports are configured.\n- Review which application tokens hold all authorizations.","fix":"- Upgrade Open Zaak to `1.27.2`, `1.28.2`, or `1.29.0`, matching your release line.\n- Rotate application tokens that hold all authorizations if they may have been misused.","status":"open","published_at":"2026-10-16T16:18:43+00:00","first_seen_at":"2026-10-23T21:57:13+00:00","triaged_at":"2026-10-25T03:45:11+00:00","updated_at":"2026-10-25T03:45:11+00:00","category":"package","confidence":0.8,"triage":{"at":"2026-10-25T03:45:11Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Open Zaak to `1.27.2`, `1.28.2`, or `1.29.0`, matching your release line.\n- Rotate application tokens that hold all authorizations if they may have been misused.","reach":"network","title":"Open Zaak: CSV import path lets authorized client read server files","impact":"high","summary":"Open Zaak's document import task does not confine the bestandspad path in uploaded CSV rows to the configured import directory. A client with an all-authorizations application token can point it at any file the Celery worker can read, and the worker copies that file into document storage where it can be downloaded.","category":"package","nicknames":[],"who_cares":["open-zaak","self-hosted","celery","document-import"],"confidence":0.8,"needs_auth":"yes","worst_case":"Server secrets and private files readable by the Celery service account are exfiltrated.","analyst_note":"","how_to_check":"- Check the installed Open Zaak version and compare it to the fixed releases listed in the fix field.\n- Look for IMPORT_DOCUMENTEN_BASE_DIR in the deployment settings to confirm whether document CSV imports are configured.\n- Review which application tokens hold all authorizations.","needs_analyst":false,"not_affected_if":["fixed-version","no-csv-document-import","narrow-token-scopes"],"who_is_affected":"Deployments running Open Zaak versions from 1.13.0 up to 1.27.2, 1.28.2, or 1.29.0 that use the document CSV import feature are exposed. The attacker needs a client application token with all authorizations, so deployments that only issue narrow tokens are less exposed. Installations on the fixed versions are not affected.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000656,"input_tokens":3464,"output_tokens":619,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-55836':14A,17A '1.13.0':102C '1.27.2':104C,194C '1.28.2':105C,195C '1.29.0':107C,197C 'absolut':145C 'account':159C 'all-author':54B,137C 'allow':168C 'api':179C 'applic':57B,140C 'attack':116C 'attacker-control':115C 'author':7A,56B,139C 'base':131C 'bestandspad':39B,118C 'case':98C 'case-ori':97C 'celeri':18B,66B,157C 'client':8A,51B,134C 'configur':47B 'confin':37B 'content':170C 'control':117C 'copi':73B,162C 'csv':3A,43B,119C 'cve':12A,15A 'data':91C 'dir':132C 'directori':49B 'document':20B,32B,77B,109C,166C,177C 'document-import':19B 'documenten':130C 'download':83B,178C 'dutch':96C 'ensur':122C 'expos':181C 'field':120C 'file':11A,64B,75B,153C,164C,187C 'fix':191C 'host':28B 'import':4A,21B,33B,48B,108C,129C 'issu':189C 'layer':94C 'let':6A 'normal':176C 'open':1A,23B,29B,84C,89C 'open-sourc':88C 'open-zaak':22B 'orient':99C 'packag':25B 'parent':148C 'parent-travers':147C 'path':5A,40B,126C,150C 'point':60B 'privat':186C 'read':9A,69B 'readabl':154C 'remain':127C 'resolv':125C 'retriev':173C 'row':44B,110C 'secret':183C 'self':27B 'self-host':26B 'server':10A,182C 'servic':93C,158C 'sourc':90C 'src/openzaak/components/documenten/tasks.py':112C 'storag':78B,167C 'suppli':143C 'task':34B 'token':58B,141C 'travers':149C 'upload':42B 'use':113C 'version':193C 'without':121C 'work':100C 'worker':67B,72B,161C 'zaak':2A,24B,30B,85C","nicknames":[],"mitigations":[],"who_affected":"Deployments running Open Zaak versions from 1.13.0 up to 1.27.2, 1.28.2, or 1.29.0 that use the document CSV import feature are exposed. The attacker needs a client application token with all authorizations, so deployments that only issue narrow tokens are less exposed. Installations on the fixed versions are not affected.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-16T16:18:43+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N","cvss_by":"security-advisories@github.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-55836","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55836","severity":null,"published_at":"2026-10-16T16:18:43+00:00","modified_at":"2026-10-16T20:04:29+00:00","first_seen_at":"2026-10-23T21:57:13+00:00","fetched_at":"2026-10-23T22:28:55+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}