CVE-2026-47244: Netty HTTP/2 Remote Code Execution Vulnerability
MODERATECVE-2026-47244 is a MODERATE (CVSS 5.3) remote code execution vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Netty HTTP/2 libraries in the Maven ecosystem. The issue involves advertised max_concurrent_streams are not enforced. Remediation is available by upgrading affected packages to version 4.2.15.Final, 4.1.135.Final.
CVE-2026-47244 at a Glance
Security Impact
CVSS: 5.3
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:L).
How to Fix CVE-2026-47244
To remediate this vulnerability, upgrade all affected Netty HTTP/2 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-http2</artifactId>
<version>4.2.15.Final</version>
</dependency><dependency>
<groupId>io.netty</groupId>
<artifactId>netty-codec-http2</artifactId>
<version>4.1.135.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-2026-47244, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=io.nettyAnalyze the terminal output to locate any version of Netty HTTP/2 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.2.15.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 HTTP/2, 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-2026-47244 Affected Netty HTTP/2 Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
io.netty:netty-codec-http2
|
Maven |
≥ 4.2.0.Final
< 4.2.15.Final
|
4.2.15.Final
|
|
io.netty:netty-codec-http2
|
Maven |
< 4.1.135.Final
|
4.1.135.Final
|
References
Frequently Asked Questions
What is CVE-2026-47244?
Which Netty HTTP/2 versions are affected?
What version fixes CVE-2026-47244?
Is netty-codec-http2 affected?
What is the CVSS score of CVE-2026-47244?
What CWE is associated with CVE-2026-47244?
How can I check Maven dependencies for CVE-2026-47244?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-5x3r-wrvg-rp6q",
"modified" : "2026-06-12T19:30:17Z",
"published" : "2026-06-08T23:02:40Z",
"aliases" : [ "CVE-2026-47244" ],
"summary" : "Netty HTTP/2: Advertised MAX_CONCURRENT_STREAMS are not enforced",
"details" : "### Impact\nDefaultHttp2Connection.DefaultEndpoint initialises maxActiveStreams/maxStreams to Integer.MAX_VALUE, and Http2Settings never inserts SETTINGS_MAX_CONCURRENT_STREAMS by default (Http2Settings.java:305-307 only clamps a user-supplied value). Unless the application explicitly calls initialSettings().maxConcurrentStreams(n), a Netty HTTP/2 server advertises no limit and enforces none locally. Each open stream allocates a DefaultStream object, PropertyMap slots, flow-controller state and IntObjectHashMap entry; with ~2^30 permissible odd stream IDs a single TCP connection can create hundreds of thousands of long-lived stream objects. This is also the precondition for CVE-2023-44487-style Rapid-Reset amplification, where the absence of a low concurrent cap multiplies backend work.\n\n### Resources\nhttps://www.rfc-editor.org/rfc/rfc7540.html#section-6.5.2",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "io.netty:netty-codec-http2"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.2.0.Final"
}, {
"fixed" : "4.2.15.Final"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.2.14.Final"
}
}, {
"package" : {
"ecosystem" : "Maven",
"name" : "io.netty:netty-codec-http2"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "4.1.135.Final"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.1.134.Final"
}
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/netty/netty/security/advisories/GHSA-5x3r-wrvg-rp6q"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-47244"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/netty/netty"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/releases/tag/netty-4.1.135.Final"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/releases/tag/netty-4.2.15.Final"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-400" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-06-08T23:02:40Z",
"nvd_published_at" : "2026-06-12T15:16:29Z"
}
}