CVE-2026-76816

low

Assigned by CNA: github_m

Published 2026-08-24 · Modified 2026-08-24

Discuss on Community Propose mitigation

CVSS v3

3.5

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

CVSS v4 NEW

—

not yet in upstream

VIR risk

3.5

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.

Predictions

Exploit likelihood

35%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

References

CWEs

CWE-20 CWE-626

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.