CVE-2026-76816 (GCVE-0-2026-76816)

Vulnerability from cvelistv5 – Published: 2026-08-24 19:53 – Updated: 2026-08-25 13:34
VLAI
Title
Netty: MQTT Topic Name and Client ID Validation Bypass
Summary
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.
Severity
3.5 (Low)
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-25 13:34 UTC
CWE
  • CWE-20 - Improper Input Validation
  • CWE-626 - Null Byte Interaction Error (Poison Null Byte)
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7637 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
netty netty Affected: >= 4.2.0.Final, < 4.1.137.Final
Affected: < 4.1.137.Final
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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