CVE-2026-75516 RabbitMQ Java client: Frame-level OOM: Math.min(maxInboundMessageBodySize, 0) defeats frame size enforcement
A malicious server or MITM attacker can cause client memory exhaustion and process termination by exploiting a frame size validation flaw in the RabbitMQ Java client.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-75516?
CVE-2026-75516 is a high-severity denial of service vulnerability in rabbitmq-java-client, published on 16 Sep 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 5.34.0, AMQConnection.start() applies Math.min(maxInboundMessageBodySize, frameMax) after Connection.Tune negotiation even though AMQP defines frameMax value zero as unlimited and ConnectionFactory.DEFAULT_FRAME_MAX is zero. When the client default and server-negotiated value are both zero, the result is passed to Utils.framePayloadLimit(int), which interprets zero as Integer.MAX_VALUE and disables the configured maxInboundMessageBodySize cap. A malicious AMQP server, or a man-in-the-middle attacker able to modify Connection.Tune and inject frames into the connection, can then send an oversized frame of any frame type, causing Frame.readFrom() to allocate a large byte array before content-level validation and potentially terminate the client process through memory exhaustion. This issue is fixed in version 5.34.0.
Weakness: CWE-770
Which versions are affected by CVE-2026-75516?
2 open source packages ship an affected version, including com.rabbitmq:amqp-client.
| Package | Affected | Fixed in |
|---|---|---|
com.rabbitmq:amqp-client Maven | All versions | 5.34.0 |
com.rabbitmq:amqp-client Maven | All versions | 5.34.0 |
How do I fix CVE-2026-75516?
Upgrade com.rabbitmq:amqp-client to 5.34.0 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-2026-75516 being exploited?
There is no known exploitation of CVE-2026-75516 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-FQ92351, CLEANSTART-2026-UX42229, CLEANSTART-2026-YJ89488, DEBIAN-CVE-2026-75516, ECHO-c374-3c74-70ef, GHSA-jh4v-gfqj-7rhx and 16 more.