Improper Restriction of XML External Entity Reference in proCertum SmartSign

proCertum SmartSign parses external XML entities from arbitrary crafted signature files, enabling SSRF and potentially allowing the reading of local files, depending on the parser's configuration. The XML External Entity (XXE) vulnerability is triggered simply by previewing a file in the file selection window, before the victim clicks “Open”. This issue was fixed in version 9.4.3.90.