protobufjs compiles protobuf definitions into JavaScript (JS) functions. In versions prior to 8.0.1 and 7.5.5, attackers can inject arbitrary code in the "type" fields of protobuf definitions, which will then execute during object decoding using that definition. Versions 8.0.1 and 7.5.5 patch the issue.
The package protobufjs before 6.11.3 are vulnerable to Prototype Pollution which can allow an attacker to add/modify properties of the Object.prototype. This vulnerability can occur in multiple ways: 1. by providing untrusted user input to util.setProperty or to ReflectionObject.setParsedOption functions 2. by parsing/loading .proto files