CVE•Published 2026-07-21•Modified 2026-07-30•1 article on news•3 live references•NVD data

CVE-2026-56817Netty · Netty

Vulnerability data via NVD (ingested)

CVSS v3.1

9.8

CRITICAL

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

EPSS percentile

Exploit Prediction Scoring System · top 76% of all CVEs

Weaknesses (CWE)

CWE-611Improper Restriction of XML External Entity Reference

Description

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, any caller that can deliver bytes to a Netty channel pipeline containing `XmlDecoder` can send XML with a `DOCTYPE` declaration to an `AsyncXMLInputFactory` instantiated with no security configuration, leaving DTD and entity handling active depending on Aalto XML async parser behavior and creating conditional XML external entity risk. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Timeline

Published 2026-07-21

Modified 2026-07-30

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). Live host counts are a Premium feature.

Shodan · vuln tag

vuln:CVE-2026-56817

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Netty Netty"

All exposed Netty Netty instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Netty"

HTTP body or banner mentions "Netty" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-56817