GHSA-93j5-89vc-pph4

RabbitMQ Java client ValueReader: Unbounded recursive table/array nesting causes StackOverflowError DoS

## Summary `ValueReader.readTable()` and `readArray()` recursively call `readFieldValue()` with no depth limit. A malicious AMQP peer can crash the client JVM by sending a deeply nested table structure. ## Vulnerable Code `src/main/java/com/rabbitmq/client/impl/ValueReader.java` lines 139-155 and 237-249: ```java private static Map<String, Object> readTable(DataInputStream in) throws IOException { long tableLength = unsignedExtend(in.readInt()); // ... while(tableIn.available() > 0) { String name = readShortstr(tableIn); Object value = readFieldValue(tableIn); // recursive call } } static Object readFieldValue(DataInputStream in) throws IOException { switch(in.readUnsignedByte()) { case 'F': value = readTable(in); // mutual recursion case 'A': value = readArray(in); // mutual recursion } } ``` ## Attack Scenario A malicious AMQP server (or MitM) sends a `connection.start` frame with ~580 levels of nested tables. Each level costs ~7 bytes (4-byte length + 1-byte key length + 1-byte key + 1-byte type tag), totaling ~4060 bytes within the 131,072 byte max frame size. With the default JVM stack (~512KB, ~864 bytes/frame), this triggers `StackOverflowError`, killing the I/O thread. Exploitable pre-authentication since `connection.start` is the very first server frame. ## Impact Denial of service. `StackOverflowError` kills the client I/O thread. ## CWE CWE-674: Uncontrolled Recursion ## Remediation Add a depth counter to `readTable`/`readArray`/`readFieldValue` and throw `MalformedFrameException` when exceeding a threshold (e.g., 32).