Official software receives regular security updates to patch newly discovered vulnerabilities. A pirated version, frozen at its release state, will never receive these updates. For example, official advisories document critical vulnerabilities in Adobe Photoshop CC 2019 version 20.0.8 and earlier that could allow for arbitrary code execution and information leakage. By using an unofficial, older version, you are knowingly leaving these security holes open for any malware on your system to exploit.