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 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.

CVSS v3 3.5 LOW

3.5^/10

CVSS v3 : LOW

Vector :

Exploitability : 2.1 / Impact : 1.4

Attack Vector ADJACENT_NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
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

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-24 20:17

Updated : 2026-09-09 21:06

NVD link : CVE-2026-76816

Mitre link : CVE-2026-76816

CVE.ORG link : CVE-2026-76816

JSON object : View

Products Affected

No product.

CWE

CWE-20

Improper Input Validation

CWE-626

Null Byte Interaction Error (Poison Null Byte)

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