Design/Logic Flaw

fs2 is a compositional, streaming I/O library for Scala. When establishing a server-mode TLSSocket using fs2-io on Node.js, the parameter requestCert = true is ignored, peer certificate verification is skipped, and the connection proceeds. The vulnerability is limited to: 1. fs2-io running on Node.js. The JVM TLS implementation is completely independent. 2. TLSSockets in server-mode. Client-mode TLSSockets are implemented via a different API. 3. mTLS as enabled via requestCert = true in TLSParameters. The default setting is false for server-mode TLSSockets. It was introduced with the initial Node.js implementation of fs2-io in 3.1.0. A patch is released in v3.2.11. The requestCert = true parameter is respected and the peer certificate is verified. If verification fails, a SSLException is raised. If using an unpatched version on Node.js, do not use a server-mode TLSSocket with requestCert = true to establish a mTLS connection.