Werk #19299: Restrict RabbitMQ inter-site broker to TLS 1.3 only

Component	User interface
Title	Restrict RabbitMQ inter-site broker to TLS 1.3 only
Date	Mar 17, 2026
Level	Trivial Change
Class	Bug Fix
Compatibility	Compatible - no manual interaction needed
Checkmk versions & editions	2.6.0b1 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT 2.5.0b2 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT 2.4.0p25 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT

The internal RabbitMQ message broker, used for inter-site communication, previously accepted both TLS 1.2 and TLS 1.3 connections. It now accepts TLS 1.3 only. With this werk we also restrict connections to the RabbitMQ management plugin to TLS 1.3.

TLS 1.2 permits cipher suites that are considered weak by modern security standards. TLS 1.3 removes all such cipher suites by design.

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