js-toml Prototype Pollution Vulnerability

QFinch assessment

A prototype pollution vulnerability in `js-toml` allows a remote attacker to add or modify properties of the global `Object.prototype` by parsing a maliciously crafted TOML input.

Potential impact

The js-toml library is vulnerable to Prototype Pollution. When parsing a TOML string containing the specially crafted key proto, an attacker can add or modify properties on the global Object.prototype. While the js-toml library itself does not contain known vulnerable "gadgets", this can lead to severe security vulnerabilities in applications that use the library. For example, if the consuming application checks for the existence of a property for authorization purposes (e.g., user.isAdmin), this vulnerability could be escalated to an authentication bypass. Other potential impacts in the application include Denial of Service (DoS) or, in some cases, Remote Code Execution (RCE), depending on the application's logic and dependencies. Any application that uses an affected version of js-toml to parse untrusted input is vulnerable. The severity of the impact, ranging from unexpected behavior to a full security compromise, is dependent on the application's specific code and its handling of object properties.