CVE-2026-44892: Netty codec http3 Denial of Service Vulnerability
HIGHCVE-2026-44892 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Netty codec http3 libraries in the Maven ecosystem. The issue involves netty has a vulnerable default configuration which leads to denial of service via unbounded http/3 header size. Remediation is available by upgrading affected packages to version 4.2.15.Final.
CVE-2026-44892 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-2026-44892
To remediate this vulnerability, upgrade all affected Netty codec http3 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-http3</artifactId>
<version>4.2.15.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-2026-44892, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=io.nettyAnalyze the terminal output to locate any version of Netty codec http3 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 codec http3, 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-2026-44892 Affected Netty codec http3 Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
io.netty:netty-codec-http3
|
Maven |
≥ 4.2.0.Final
< 4.2.15.Final
|
4.2.15.Final
|
References
Frequently Asked Questions
What is CVE-2026-44892?
Which Netty codec http3 versions are affected?
What version fixes CVE-2026-44892?
Is netty-codec-http3 affected?
What is the CVSS score of CVE-2026-44892?
What CWE is associated with CVE-2026-44892?
How can I check Maven dependencies for CVE-2026-44892?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-c2rx-5r8w-8xr2",
"modified" : "2026-06-12T19:27:28Z",
"published" : "2026-06-08T19:02:16Z",
"aliases" : [ "CVE-2026-44892" ],
"summary" : "Netty has a Vulnerable Default Configuration Which Leads to Denial of Service via Unbounded HTTP/3 Header Size",
"details" : "### Summary\nThe default configuration of the `Http3ConnectionHandler` in the Netty HTTP/3 codec lacks an enforced maximum header size limit. When a peer does not explicitly specify `HTTP3_SETTINGS_MAX_FIELD_SECTION_SIZE`, the implementation defaults to an unbounded limit. This insecure default configuration allows a malicious client or server to send an enormous number of headers, leading to a memory exhaustion Denial of Service via an `OutOfMemoryError`.\n\n### Details\nNetty securely limits header sizes for older protocols. In HTTP/1.1, Netty strictly enforces an `8192`-byte limit out-of-the-box via `HttpObjectDecoder`. For HTTP/2, while RFC 9113 specifies that `SETTINGS_MAX_HEADER_LIST_SIZE` defaults to `unlimited`, Netty securely overrides this RFC default by enforcing an `8192`-byte limit (`Http2CodecUtil.DEFAULT_HEADER_LIST_SIZE`).\n\nHowever, this secure-by-default configuration is missing in the HTTP/3 implementation. While Netty provides a mechanism to configure the maximum header field section size via `Http3Settings`, its out-of-the-box behaviour strictly follows RFC 9114's unlimited default.\n\nBecause many developers rely on the framework's default configurations and basic constructors, their applications are unknowingly left vulnerable. This nearly infinite default limit is passed into `Http3FrameCodec#newFactory` and stored as `maxHeaderListSize` inside `Http3FrameCodec`.\n\nA bad actor can continuously send HTTP/3 headers within a connection, exploiting the insecure default configuration to consume server memory unconditionally until the application crashes with an `OutOfMemoryError`.\n\n### Impact\nDenial of Service via memory exhaustion. All applications using Netty's HTTP/3 codec with its default configuration are impacted.",
"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-http3"
},
"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"
}
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/netty/netty/security/advisories/GHSA-c2rx-5r8w-8xr2"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-44892"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/netty/netty"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/releases/tag/netty-4.2.15.Final"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-1188", "CWE-400" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-06-08T19:02:16Z",
"nvd_published_at" : "2026-06-12T05:16:32Z"
}
}