Kivitendo before 3.9.2 allows XXE injection. By uploading an electronic invoice in the ZUGFeRD format, it is possible to read and exfiltrate files from the server's filesystem.
https://github.com/kivitendo/kivitendo-erp/commit/f6ba56bd8d22a428534057589baace6b7bfdf2e9
https://github.com/kivitendo/kivitendo-erp/commit/1286dee72f9919166178d0cdb5f52f13b0f7d4de