CVE-2026-61634 RabbitMQ Java client accepts broker frames larger than the negotiated AMQP frame_max
A malicious broker can cause client-side denial of service by sending oversized frames that bypass negotiated limits in the RabbitMQ Java client library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-61634?
CVE-2026-61634 is a denial of service vulnerability in rabbitmq-java-client, published on 18 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.33.0, the AMQP connection tuning path records the negotiated AMQP frame_max value, but src/main/java/com/rabbitmq/client/impl/SocketFrameHandler.java and NettyFrameHandlerFactory continue to validate broker-controlled frame payload lengths against maxInboundMessageBodySize because the negotiated limit is not applied consistently through setMaxInboundFramePayloadSize. A malicious or compromised broker can send a method frame larger than the negotiated frame_max during or after connection establishment, causing the client to allocate and decode a protocol-invalid frame instead of rejecting it with MalformedFrameException. The protocol violation can disrupt the affected connection and cause client-side denial of service. This issue is fixed in version 5.33.0.
Weakness: CWE-20
Which versions are affected by CVE-2026-61634?
2 open source packages ship an affected version, including com.rabbitmq:amqp-client.
| Package | Affected | Fixed in |
|---|---|---|
com.rabbitmq:amqp-client Maven | All versions | 5.33.0 |
com.rabbitmq:amqp-client Maven | All versions | 5.33.0 |
How do I fix CVE-2026-61634?
Upgrade com.rabbitmq:amqp-client to 5.33.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-61634 being exploited?
There is no known exploitation of CVE-2026-61634 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-KN86223, DEBIAN-CVE-2026-61634, ECHO-18ae-a032-1738, GHSA-5xwg-cfvj-gff5, MINI-599w-36v5-45p5, MINI-fh8r-cgh7-wxc5 and 14 more.