CVE-2026-63336: RabbitMQ Java client: TrustEverythingTrustManager used by default in useSslProtocol() enables MITM

Vulnerability Summary

com.rabbitmq.client.TrustEverythingTrustManager accepts ANY TLS certificate (including null chains) and is used as the default trust manager when calling ConnectionFactory.useSslProtocol() without arguments. Combined with hostname verification being disabled by default, this enables trivial man-in-the-middle attacks.

Affected Components

- com.rabbitmq.client.TrustEverythingTrustManager — accepts any certificate - com.rabbitmq.client.ConnectionFactory.useSslProtocol() — uses TrustEverythingTrustManager - Hostname verification disabled by default (enableHostnameVerification() must be called explicitly) - com.rabbitmq.client.ConnectionFactory.getPassword() — returns plaintext with no redaction - Default port 5672 (plaintext) with PLAIN SASL — credentials sent unencrypted

POC (Verified on Java 21, amqp-client 5.25.0)

java // TrustEverythingTrustManager accepts ANY certificate including null TrustEverythingTrustManager tm = new TrustEverythingTrustManager(); tm.checkServerTrusted(null, "RSA"); // No exception — accepts null cert chain tm.getAcceptedIssuers(); // Returns empty array — trusts all CAs

// ConnectionFactory defaults ConnectionFactory factory = new ConnectionFactory(); factory.useSslProtocol(); // Uses TrustEverythingTrustManager internally // enableHostnameVerification() NOT called by default

// Credential exposure factory.setPassword("secretpassword123"); factory.getPassword(); // Returns "secretpassword123" — no redaction

// Default plaintext port factory.getPort(); // 5672 (plaintext, not 5671/TLS)

// PLAIN SASL sends cleartext credentials PlainMechanism pm = new PlainMechanism(); // handleChallenge() sends username+password in cleartext

Attack Scenarios

1. MITM: Attacker presents self-signed cert → TrustEverythingTrustManager accepts it → all RabbitMQ traffic intercepted 2. Credential theft: Default plaintext port (5672) + PLAIN SASL = credentials readable on network 3. DNS rebinding: No hostname verification → attacker DNS record → MITM without cert 4. Logging exposure: getPassword() returns plaintext → credentials in logs/stack traces

Suggested Fix 1. Deprecate TrustEverythingTrustManager — it should never be used in production 2. useSslProtocol() should use the JVM default trust store, not TrustEverything 3. Enable hostname verification by default 4. Redact password in getPassword() or remove the public getter 5. Warn when using PLAIN SASL without TLS