Improper Restriction of XML External Entity Reference
ModbusPal 1.6b is vulnerable to an XML External Entity (XXE) attack. Projects are saved as .xmpp files and automations can be exported as .xmpa files, both XML-based, which are vulnerable to XXE injection. Sending a crafted .xmpp or .xmpa file to a user, when opened/imported in ModbusPal, will return the contents of any local files to a remote attacker.
CWE-611 - Improper Restriction of XML External Entity Reference
Listed 4th in the 'OWASP Top Ten', XML External Entities (XXE) vulnerability allows attackers to provide an XML input that contains an external entity. When the XML is parsed, it can cause data extraction and manipulation, execution of commands, denial-of-service attacks, and server-side request forgery.