An issue was discovered in tangro Business Workflow before 1.18.1. No (or broken) access control checks exist on the /api/document//attachments API endpoint. Knowing a document ID, an attacker can list all the attachments of a workitem, including their respective IDs. This allows the attacker to gather valid attachment IDs for workitems that do not belong to them.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-26176
• https://blog.to.com/advisory-tangro-bwf-1-17-5-multiple-vulnerabilities/
• https://www.tangro.de/