GHSA-68mj-5wr7-6fgg
RabbitMQ Java client ValueReader: Oversized LongString/bytes length triggers OOM via unchecked allocation
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Maven | com.rabbitmq:amqp-client | < 5.33.1 | 5.33.1 |
Details
As written in the advisory (Markdown source, shown as plain text).
## Summary
`ValueReader.readBytes()` allocates a byte array sized by a wire-declared content length without validating it against actual frame data. A malicious AMQP peer triggers OOM by declaring a ~2GB string/bytes field.
## Vulnerable Code
`src/main/java/com/rabbitmq/client/impl/ValueReader.java` lines 83-95:
```java
private static byte[] readBytes(final DataInputStream in) throws IOException {
final long contentLength = unsignedExtend(in.readInt());
if(contentLength < Integer.MAX_VALUE) {
final byte[] buffer = new byte[(int)contentLength]; // allocates before reading
in.readFully(buffer);
return buffer;
}
}
```
## Attack Scenario
A malicious AMQP server sends a LongString field (type tag 'S') with declared length `0x7FFFFFFE` (2,147,483,646). The check `contentLength < Integer.MAX_VALUE` passes. `new byte[2147483646]` attempts ~2GB allocation, causing `OutOfMemoryError` before `readFully()` attempts to read data.
The allocation size is attacker-controlled and is NOT validated against the frame size or `TruncatedInputStream` bounds. Exploitable pre-authentication via `connection.start` server-properties table.
## Impact
Denial of service via JVM `OutOfMemoryError`. Crashes the entire JVM.
## CWE
CWE-789: Memory Allocation with Excessive Size Value
## Remediation
Validate `contentLength` against the frame's remaining bytes or the negotiated max frame size (default 131,072) before allocating.
References
External links from the advisory. They lead to third-party sites.
- https://github.com/rabbitmq/rabbitmq-java-client/security/advisories/GHSA-68mj-5wr7-6fgg
- https://github.com/rabbitmq/rabbitmq-java-client/pull/2007
- https://github.com/rabbitmq/rabbitmq-java-client/pull/2008
- https://github.com/rabbitmq/rabbitmq-java-client/commit/388209356c6478088efce4d8a07b68e73837a7a0
- https://github.com/rabbitmq/rabbitmq-java-client/commit/6a87a8dcdc8b4cc4b961a7cdd388276446e5dfb2
- https://github.com/rabbitmq/rabbitmq-java-client
- https://github.com/rabbitmq/rabbitmq-java-client/releases/tag/v5.33.1