CVE•Published 2026-08-24•Modified 2026-10-12•0 articles on news•3 live references•NVD data

CVE-2026-76816

Vulnerability data via NVD (ingested)

CVSS v3.1

3.5

LOW

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

EPSS percentile

Exploit Prediction Scoring System · top 94% of all CVEs

Weaknesses (CWE)

CWE-20Improper Input Validation CWE-626Null Byte Interaction Error (Poison Null Byte)

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.

Timeline

Published 2026-08-24

Modified 2026-10-12

External references

NVD MITRE VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-76816

Hosts Shodan has explicitly fingerprinted as vulnerable.

More intel sources (5)

Shodan report

vuln:CVE-2026-76816

Country / ASN / product breakdown for the vuln query.

Censys

vulnerabilities.cve_id: CVE-2026-76816

Censys host search filtered to this CVE id.

grep.app

CVE-2026-76816