CVE-2026-76816

Published: Aug 24, 2026Modified: Aug 25, 2026

3.5

Vector

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

Exploitability: 2.1 / Impact: 1.4

Source: security-advisories@github.com (Secondary)

Description

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.

Related CWEs

CWE-20

Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

CWE-626

Null Byte Interaction Error (Poison Null Byte)

The product does not properly handle null bytes or NUL characters when passing data between different representations or components.

References (3)

https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7

Source: security-advisories@github.com

https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961

Source: security-advisories@github.com

https://github.com/netty/netty/security/advisories/GHSA-43fm-7cxg-hf3j

Source: security-advisories@github.com

Timeline

No history available yet.