CVE-2026-67416: RabbitMQ AMQP 1.0 Symbolic Body Descriptor Prefix Collisions Bypass Validation
Summary
CVE-2026-67416: RabbitMQ: AMQP 1.0 symbolic body descriptor prefix collisions bypass validation. Affects rabbitmq across 4 version ranges.
>= 4.0.0, < 4.0.24
>= 4.1.0, < 4.1.15
>= 4.2.0, < 4.2.10
>= 4.3.0, < 4.3.4
Fixed in 4 releases; the minimum fixed version depends on the release line you run. How to fix ↓
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Background
RabbitMQ is a widely used open-source messaging and streaming broker that facilitates communication between applications through message queuing. It supports multiple messaging protocols, including AMQP, and is known for its reliability and scalability. The software is designed to handle high-throughput messaging scenarios, making it a popular choice for microservices architectures. However, certain versions of RabbitMQ are vulnerable to a specific issue related to the AMQP 1.0 protocol, which can lead to misclassification of message body descriptors.
Vulnerability Detail
The vulnerability arises from the optimized AMQP 1.0 server_mode parser in RabbitMQ versions 4.0.0 to 4.0.24, 4.1.15, 4.2.10, and 4.3.4. This parser matches the textual prefixes of symbolic data, sequence, and value body descriptors without verifying their encoded symbol lengths. An authenticated AMQP 1.0 publisher with write permission can exploit this flaw by submitting a well-formed unknown descriptor that begins with a registered body descriptor. As a result, RabbitMQ misclassifies and stores the bytes as a standard body section, which can lead to strict AMQP 1.0 consumers terminating while decoding the stored entry. This misclassification can also cause AMQP 0-9-1 or other cross-protocol conversions to perform full body decoding, potentially terminating the consumer protocol process. While the broker remains operational, this issue does not bypass routing or authorization, but it can lead to repeated failures in message delivery.
How To Fix
Fixed versions by release line
The minimum fixed version depends on the release line you run.
-
>= 4.0.0, < 4.0.244.0.24 -
>= 4.1.0, < 4.1.154.1.15 -
>= 4.2.0, < 4.2.104.2.10 -
>= 4.3.0, < 4.3.44.3.4
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Workaround
Currently, there are no specific workarounds mentioned for this vulnerability. The best course of action is to update to the patched versions as soon as possible.
Conclusion
CVE-2026-67416 represents a significant vulnerability in RabbitMQ that can lead to message misclassification and potential consumer termination. Users are strongly advised to update to the patched versions to ensure the security and reliability of their messaging systems.
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FAQ
CVE-2026-67416 is a vulnerability in RabbitMQ that allows an authenticated AMQP 1.0 publisher to bypass validation of symbolic body descriptor prefixes, leading to potential misclassification of message bodies.
The affected versions include RabbitMQ 4.0.0 to 4.0.24, 4.1.0 to 4.1.15, 4.2.0 to 4.2.10, and 4.3.0 to 4.3.4.
You can use the Vulert platform to monitor and alert for open-source vulnerabilities in your software. By using the Vulert playground, you can check if your application is affected by this vulnerability without needing to sign up.
The vulnerability can lead to message misclassification, causing strict AMQP 1.0 consumers to terminate and potentially affecting message delivery in cross-protocol conversions.
While there are no specific workarounds, it is crucial to prioritize updating to a patched version to mitigate the risk associated with this vulnerability.
References
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