CVE-2026-106121: RabbitMQ: JSONReader in the default JSON-RPC mapper never terminates on truncated input, causing DoS

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-10-06 · updated 2026-10-09
Weakness: CWE-835

Description

The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.37.0, com.rabbitmq.tools.json.JSONReader.read() fails to terminate when input ends inside a quoted string or a line comment because its string and whitespace scanners do not stop at CharacterIterator.DONE. The default DefaultJsonRpcMapper passes JSON-RPC message bodies to this parser for JsonRpcServer and client replies. A truncated string causes the parser to append replacement end markers until heap exhaustion, while a line comment without a terminating newline can keep a thread consuming CPU indefinitely, resulting in denial of service. This issue is fixed in version 5.37.0.

Affected products

rabbitmq-java-client: before 5.37.0 — fixed in 5.37.0
com.rabbitmq amqp-client: before 5.36.1
rabbitmq-java-client: before 5.36.1

How to fix

Upgrade to a fixed version: rabbitmq-java-client 5.37.0. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-106121 or the next vulnerability affects your stack