xml-crypto is an XML digital signature and encryption library for Node.js. An attacker may be able to exploit a vulnerability in versions prior to 6.0.1, 3.2.1, and 2.1.6 to bypass authentication or authorization mechanisms in systems that rely on xml-crypto for verifying signed XML documents. The vulnerability allows an attacker to modify a valid signed XML message in a way that still passes signature verification checks. For example, it could be used to alter critical identity or access control attributes, enabling an attacker to escalate privileges or impersonate another user. Users of versions 6.0.0 and prior should upgrade to version 6.0.1 to receive a fix. Those who are still using v2.x or v3.x should upgrade to patched versions 2.1.6 or 3.2.1, respectively.