Orthanc versions before 1.12.2 are affected by a reflected cross-site scripting (XSS) vulnerability. The vulnerability was present in the server's error reporting.

A XSS payload can be uploaded as a DICOM study and when a user tries to view the infected study inside the Osimis WebViewer the XSS vulnerability gets triggered. If exploited, the attacker will be able to execute arbitrary JavaScript code inside the victim's browser.

Orthanc before 1.12.0 allows authenticated users with access to the Orthanc API to overwrite arbitrary files on the file system, and in specific deployment scenarios allows the attacker to overwrite the configuration, which can be exploited to trigger Remote Code Execution (RCE).