Forge (also called node-forge) is a native implementation of Transport Layer Security in JavaScript. Prior to 1.4.1, the affected implementation used forge.tls.createConnection(), c.session.serverCertificate, RSA key exchange to process the relevant input or security decision. node-forge's TLS client checked the wrong property when deciding whether a server certificate was missing. A malicious TLS server or on-path peer could omit the Certificate message and reach code that dereferenced the absent certificate, causing an uncaught exception and terminating the connection or process. This issue is fixed in version 1.4.1.