CVE-2026-59902: Netty Memory Exhaustion Vulnerability
HIGHCVE-2026-59902 is a HIGH (CVSS 7.5) memory exhaustion vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Netty libraries in the Maven ecosystem. The issue involves memory exhaustion in sctpmessagecompletionhandler. Remediation is available by upgrading affected packages to version 4.2.17.Final, 4.1.137.Final.
CVE-2026-59902 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-2026-59902
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-transport-sctp</artifactId>
<version>4.2.17.Final</version>
</dependency><dependency>
<groupId>io.netty</groupId>
<artifactId>netty-transport-sctp</artifactId>
<version>4.1.137.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-2026-59902, 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 4.2.17.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-2026-59902 Affected Netty Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
io.netty:netty-transport-sctp
|
Maven |
≥ 4.2.0.Final
< 4.2.17.Final
|
4.2.17.Final
|
|
io.netty:netty-transport-sctp
|
Maven |
< 4.1.137.Final
|
4.1.137.Final
|
References
Frequently Asked Questions
What is CVE-2026-59902?
Which Netty versions are affected?
What version fixes CVE-2026-59902?
Is netty-transport-sctp affected?
What is the CVSS score of CVE-2026-59902?
What CWE is associated with CVE-2026-59902?
How can I check Maven dependencies for CVE-2026-59902?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-2qj4-mmr9-4v2f",
"modified" : "2026-08-17T17:50:49Z",
"published" : "2026-08-17T17:50:49Z",
"aliases" : [ "CVE-2026-59902" ],
"summary" : "Netty: Memory Exhaustion in SctpMessageCompletionHandler",
"details" : "### Summary\nSctpMessageCompletionHandler does not limit the total size of buffered fragments, allowing an unauthenticated attacker to cause an OutOfMemoryError by sending large SCTP fragments.\n\n### Details\n`io.netty.handler.codec.sctp.SctpMessageCompletionHandler` buffers fragments for incomplete SCTP messages. The fix for CVE-2026-46340 fixed unbounded memory growth by introducing limits on the number of concurrent incomplete messages (maxIncompleteSctpMessages) and the number of fragments per message (maxFragments).\n\nWhile the count of fragments is now bounded, the handler still does not enforce a maximum size in bytes.\n\nWith the default limits of 128 messages and 128 fragments, and a typical max SCTP chunk size of 64KB, an attacker can consume up to ~1GB per connection. By opening a small number of concurrent connections, an attacker can easily exhaust the server's memory, causing an OutOfMemoryError.\n\n### Impact\nMemory Exhaustion. Any application using Netty's SCTP transport with SctpMessageCompletionHandler is 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-transport-sctp"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.2.0.Final"
}, {
"fixed" : "4.2.17.Final"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.2.16.Final"
}
}, {
"package" : {
"ecosystem" : "Maven",
"name" : "io.netty:netty-transport-sctp"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "4.1.137.Final"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.1.136.Final"
}
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/netty/netty/security/advisories/GHSA-2qj4-mmr9-4v2f"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/pull/17213"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/pull/17217"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/netty/netty"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/releases/tag/netty-4.1.137.Final"
}, {
"type" : "WEB",
"url" : "https://github.com/netty/netty/releases/tag/netty-4.2.17.Final"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-400" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-08-17T17:50:49Z",
"nvd_published_at" : null
}
}