CVE-2026-73507: Netty Denial of Service Vulnerability
HIGHCVE-2026-73507 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Netty libraries in the Maven ecosystem. The issue involves denial of service in xmlframedecoder via cpu exhaustion. Remediation is available by upgrading affected packages to version 4.2.16.Final, 4.1.136.Final.
CVE-2026-73507 at a Glance
Security Impact
CVSS: 7.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
How to Fix CVE-2026-73507
To remediate this vulnerability, upgrade all affected Netty dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-codec-xml</artifactId>
<version>4.2.16.Final</version>
</dependency><dependency>
<groupId>io.netty</groupId>
<artifactId>netty-codec-xml</artifactId>
<version>4.1.136.Final</version>
</dependency>Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:tree -Dincludes=io.nettyHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-73507, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=io.nettyAnalyze the terminal output to locate any version of Netty in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.2.16.Final), your application is affected.
Note: The mvn dependency:tree -Dincludes=io.netty command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Netty, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-73507 Affected Netty Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
io.netty:netty-codec-xml
|
Maven |
≥ 4.2.0.Final
< 4.2.16.Final
|
4.2.16.Final
|
|
io.netty:netty-codec-xml
|
Maven |
< 4.1.136.Final
|
4.1.136.Final
|
References
Frequently Asked Questions
What is CVE-2026-73507?
Which Netty versions are affected?
What version fixes CVE-2026-73507?
Is netty-codec-xml affected?
What is the CVSS score of CVE-2026-73507?
What CWE is associated with CVE-2026-73507?
How can I check Maven dependencies for CVE-2026-73507?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-v74w-7mr3-4qg3",
"modified" : "2026-08-13T14:25:43Z",
"published" : "2026-07-24T16:53:04Z",
"aliases" : [ "CVE-2026-73507" ],
"summary" : "Netty: Denial of Service in XmlFrameDecoder via CPU Exhaustion",
"details" : "### Summary\nAn attacker can cause Denial of Service by sending a specially crafted malicious XML payload (e.g., repeated `</` characters) to a Netty server utilizing XmlFrameDecoder, causing the server's EventLoop thread to exhaust CPU resources and become unresponsive.\n\n### Details\n`io.netty.handler.codec.xml.XmlFrameDecoder` suffers from a vulnerability resulting in CPU exhaustion. When `<` followed by `/` is encountered, the decoder scans the remaining buffer for a closing `>`.\nBecause the parser state is not saved between `decode()` invocations, an attacker can trickle-feed a payload of `</` characters. This forces the decoder to repeatedly rescan the entire accumulated buffer. A 1MB `maxFrameLength` is enough to completely hang a server's thread while it loops endlessly.\n\n### Impact\nDenial of Service via CPU Exhaustion. Any application utilizing Netty's XmlFrameDecoder is impacted. An unauthenticated remote attacker can exploit this flaw by sending a modest amount of malformed XML data to an exposed port.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "io.netty:netty-codec-xml"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.2.0.Final"
}, {
"fixed" : "4.2.16.Final"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.2.15.Final"
}
}, {
"package" : {
"ecosystem" : "Maven",
"name" : "io.netty:netty-codec-xml"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "4.1.136.Final"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.1.135.Final"
}
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/netty/netty/security/advisories/GHSA-v74w-7mr3-4qg3"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/pull/17063"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/pull/17065"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/netty/netty"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/releases/tag/netty-4.1.136.Final"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/releases/tag/netty-4.2.16.Final"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-400" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-07-24T16:53:04Z",
"nvd_published_at" : null
}
}