CVE-2026-57216: rabbitmq server Auth Bypass

Description

RabbitMQ is a messaging and streaming broker. Prior to 3.13.15, 4.0.20, 4.1.11, and 4.2.6, AMQP 0-9-1, AMQP 1.0, and Stream Protocol authentication can allow a loopback-restricted user such as guest to connect remotely when traffic is accepted through a trusted PROXY-protocol path and the backend listener is loopback-bound because the loopback check uses the listener-side socket address instead of the real client source. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6.

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CVSS v3.1 Score

6.8

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0047

Probability of exploitation

0.38%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-287 Improper Authentication

Affected Products

Vendor	Product	Versions
broadcom	rabbitmq_server	3.13.0 — 4.2.6

References

Advisories & Patches

https://github.com/rabbitmq/rabbitmq-server/commit/7273c9eb6920abcde17b892dbe97ccaf906ead47 https://github.com/rabbitmq/rabbitmq-server/commit/9f8c39fcf0acbc43080ee7017a62a02832114112 https://github.com/rabbitmq/rabbitmq-server/pull/15936 https://github.com/rabbitmq/rabbitmq-server/pull/15940 https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-36m6-588r-vqcw https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-36m6-588r-vqcw

Exploits

https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-36m6-588r-vqcw https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-36m6-588r-vqcw

Other References

https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.6

Frequently Asked Questions

What is CVE-2026-57216? +

RabbitMQ is a messaging and streaming broker. Prior to 3.13.15, 4.0.20, 4.1.11, and 4.2.6, AMQP 0-9-1, AMQP 1.0, and Stream Protocol authentication can allow a loopback-restricted user such as guest to connect remotely when traffic is accepted through a trusted PROXY-protocol path and the backend listener is loopback-bound because the loopback check uses the listener-side socket address instead of the real client source. This issue is fixed in versions 3.13.15, 4.0.20, 4.1.11, and 4.2.6. It has a CVSS v3.1 base score of 6.8 (MEDIUM).

How severe is CVE-2026-57216? +

CVE-2026-57216 has a CVSS v3.1 score of 6.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0047, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-57216? +

CVE-2026-57216 affects products from broadcom, specifically: rabbitmq_server. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-57216? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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