LOW 3.5 NVD
CVE-2026-76816
Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client ide
Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client identifiers, will topics, usernames, and PUBLISH topic names before encoding, allowing prohibited null bytes in MQTT UTF-8 string fields and potentially causing routing, access-control, or identity mismatches in downstream brokers. The vulnerability is exploitable when an application uses Netty's MQTT encoder to construct messages from user-controlled input. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.
References
- https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7
- https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961
- https://github.com/netty/netty/security/advisories/GHSA-43fm-7cxg-hf3j
This low severity vulnerability with a CVSS score of 3.5 was published on 2026-08-24 via NVD.
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