CVE-2026-63337: The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with Rabbit

Q: How do I fix CVE-2026-63337?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Q: Is CVE-2026-63337 being exploited?

CVE-2026-63337 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-63337 affect?

CVE-2026-63337 affects affected software. Severity is high (CVSS 7.5). The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.33.0, com.rabbitmq.tools.jsonrpc.ProcedureDescription receives a javaReturnType value in an untrusted system.

Q: How urgent is CVE-2026-63337?

Priority 41/100. High severity; CISA SSVC: public proof of concept

This month

HIGH 7.5

CVE-2026-63337 is a high-severity flaw (CVSS 7.5) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.33.0, com.rabbitmq.tools.jsonrpc.ProcedureDescription receives a javaReturnType value in an untrusted system.describe response and passes it through JSONUtil.tryFill, setJavaReturnType, and computeReturnTypeAsJavaClass to Class.forName(javaReturnType) with initialization enabled. An attacker able to answer the JsonRpc

Why this priority

High severity
CISA SSVC: public proof of concept

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Passive
EPSS exploit chance	0.6% (top 54%)
CISA exploited list	No
Weakness	CWE-470
Published	2026-08-18
Last modified	2026-10-22

Publisher (CNA): GitHub, Inc.

Last updated 2026-10-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-08-18Published CVE record published
2026-10-22 22:10 UTCUpdated Record last modified

Exact fixes by distribution

Maven · com.rabbitmq:amqp-client · FIXED · 5.33.0 · vulnerable: < 5.33.0 · source

Set com.rabbitmq:amqp-client to 5.33.0 or later in pom.xml or build.gradle, then rebuild and redeploy.

Fedora 46 · kwin-zones · FIXED · 1.0.13-1.fc46 · FEDORA-2026-95888f332b · source

sudo dnf upgrade --advisory=FEDORA-2026-95888f332b

Fedora ELN · nginx-mod-brotli · FIXED · 1.0.0~rc-16.eln159 · FEDORA-2026-501a6a8273 · source

sudo dnf upgrade --advisory=FEDORA-2026-501a6a8273

Debian 12 · rabbitmq-java-client · NO FIX YET

Debian 13 · rabbitmq-java-client · NO FIX YET

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-63337?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-63337 being exploited?

CVE-2026-63337 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-63337 affect?

CVE-2026-63337 affects affected software. Severity is high (CVSS 7.5). The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.33.0, com.rabbitmq.tools.jsonrpc.ProcedureDescription receives a javaReturnType value in an untrusted system.

How urgent is CVE-2026-63337?

Priority 41/100. High severity; CISA SSVC: public proof of concept

Software pages

Java vulnerabilities

References

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