Vulnerabilities in pkg:maven/io.netty/netty-codec-classes-quic

PACKAGE
Advisory Identifier: GHSA-cq4q-cv5g-r8q5
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Advisory Summary

CVE-2026-50009 is a MODERATE (CVSS 4.8) quic stateless reset token material vulnerability (CWE-330: Use of Insufficiently Random Values) affecting Netty libraries in the Maven ecosystem. The issue involves quic stateless reset token material exposed through header-visible connection ids. Remediation is available by upgrading affected packages to version 4.2.15.Final.

2 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:maven/io.netty/netty-codec-classes-quic

2 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:maven/io.netty/netty-codec-classes-quic. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-cq4q-cv5g-r8q5 CVE-2026-50009 MODERATE Netty: QUIC stateless reset token material exposed through header-visible connection IDs
GHSA-cmm3-54f8-px4j CVE-2026-44894 HIGH Netty's Default QUIC token handler accepts any client-supplied token

CVE-2026-50009 at a Glance

CVE Identifier CVE-2026-50009
GHSA Identifier GHSA-cq4q-cv5g-r8q5
Severity MODERATE
CVSS v3.1 Base Score 4.8
CWE Classification CWE-330: Use of Insufficiently Random Values
Affected Product Netty
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 4.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity None (I:N)
Availability Low (A:L)

How to Fix CVE-2026-50009

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.

io.netty:netty-codec-classes-quic fixed: 4.2.15.Final 
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-codec-classes-quic</artifactId>
    <version>4.2.15.Final</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=io.netty

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-50009, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=io.netty

Analyze 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 4.2.15.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-330: Use of Insufficiently Random Values, where the product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers. 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

### Summary Netty QUIC exposes the stateless reset token on the network path when using the default HMAC-based connection-ID and stateless-reset-token generators. The reset token for the server's current source connection ID can be derived from bytes that appear as the connection ID in QUIC headers after a source-CID rotation. An on-path attacker observing the headers can use the token to perform a Denial of Service by sending a spoofed Stateless Reset packet. ### Details The sign-based connection ID generator (HmacSignQuicConnectionIdGenerator) and reset token generator (HmacSignQuicResetTokenGenerator) both evaluate HMAC-SHA256 with the same JVM-wide static key (io.netty.handler.codec.quic.Hmac). During source CID rotation (QuicheQuicChannel.newSourceConnectionIds), the current server source CID C is used as input to produce the next CID N. The stateless reset token for C is defined over HMAC(K, C), specifically the first 16 bytes. The next CID N is the first L bytes of the same digest, where L = |C|. Whenever L ≥ 16, the first 16 bytes of N are exactly the stateless reset token for C. Because N is carried in QUIC headers as a connection ID, an observer can read the headers and learn the reset token without decrypting the payload. This directly violates RFC 9000 https://datatracker.ietf.org/doc/html/rfc9000#name-calculating-a-stateless-res: `The stateless reset token MUST be difficult to guess.` Additionally https://datatracker.ietf.org/doc/html/rfc9000#name-stateless-reset-oracle ### Impact Information Disclosure and Denial of Service. An on-path attacker can obtain the stateless reset token from the connection ID header and attempt to abruptly close the client side of the connection by sending a spoofed Stateless Reset datagram.

CVE-2026-50009 Affected Netty Versions

1 component(s)
Fixed Versions:
4.2.15.Final
Product / Package Ecosystem Affected Versions Fixed Version
io.netty:netty-codec-classes-quic
maven/io.netty/netty-codec-classes-quic
Maven
≥ 4.2.0.Final
< 4.2.15.Final
4.2.15.Final

References

GitHub Advisory / Wiki ADVISORY
https://github.com/netty/netty/security/advisories/GHSA-cq4q-cv5g-r8q5
NVD — CVE-2026-50009 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-50009
Netty Source Repository REPOSITORY
https://github.com/netty/netty
Netty Release RELEASE
https://github.com/netty/netty/releases/tag/netty-4.2.15.Final

Frequently Asked Questions

What is CVE-2026-50009?
CVE-2026-50009 is a security vulnerability in Netty involving QUIC stateless reset token material exposed through header-visible connection IDs under CWE-330: Use of Insufficiently Random Values.
Which Netty versions are affected?
Affected versions include releases prior to 4.2.15.Final across affected packages: io.netty:netty-codec-classes-quic.
What version fixes CVE-2026-50009?
Upgrading to 4.2.15.Final (or the latest patched release for your respective branch) resolves the vulnerability.
Is netty-codec-classes-quic affected?
Yes, io.netty:netty-codec-classes-quic is affected in releases prior to 4.2.15.Final. Upgrade your dependency to 4.2.15.Final or later.
What is the CVSS score of CVE-2026-50009?
CVE-2026-50009 has a CVSS v3.1 base score of 4.8 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L.
What CWE is associated with CVE-2026-50009?
CVE-2026-50009 is classified under CWE-330: Use of Insufficiently Random Values (The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.).
How can I check Maven dependencies for CVE-2026-50009?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=io.netty'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-cq4q-cv5g-r8q5",
  "modified" : "2026-06-15T20:44:20Z",
  "published" : "2026-06-15T20:44:20Z",
  "aliases" : [ "CVE-2026-50009" ],
  "summary" : "Netty: QUIC stateless reset token material exposed through header-visible connection IDs",
  "details" : "### Summary\nNetty QUIC exposes the stateless reset token on the network path when using the default HMAC-based connection-ID and stateless-reset-token generators. The reset token for the server's current source connection ID can be derived from bytes that appear as the connection ID in QUIC headers after a source-CID rotation. An on-path attacker observing the headers can use the token to perform a Denial of Service by sending a spoofed Stateless Reset packet.\n\n### Details\nThe sign-based connection ID generator (HmacSignQuicConnectionIdGenerator) and reset token generator (HmacSignQuicResetTokenGenerator) both evaluate HMAC-SHA256 with the same JVM-wide static key (io.netty.handler.codec.quic.Hmac).\n\nDuring source CID rotation (QuicheQuicChannel.newSourceConnectionIds), the current server source CID C is used as input to produce the next CID N. The stateless reset token for C is defined over HMAC(K, C), specifically the first 16 bytes. The next CID N is the first L bytes of the same digest, where L = |C|.\n\nWhenever L ≥ 16, the first 16 bytes of N are exactly the stateless reset token for C. Because N is carried in QUIC headers as a connection ID, an observer can read the headers and learn the reset token without decrypting the payload.\n\nThis directly violates RFC 9000\nhttps://datatracker.ietf.org/doc/html/rfc9000#name-calculating-a-stateless-res: `The stateless reset token MUST be difficult to guess.`\nAdditionally https://datatracker.ietf.org/doc/html/rfc9000#name-stateless-reset-oracle\n\n### Impact\nInformation Disclosure and Denial of Service. An on-path attacker can obtain the stateless reset token from the connection ID header and attempt to abruptly close the client side of the connection by sending a spoofed Stateless Reset datagram.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "io.netty:netty-codec-classes-quic"
    },
    "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-cq4q-cv5g-r8q5"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-50009"
  }, {
    "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-200", "CWE-330" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-15T20:44:20Z",
    "nvd_published_at" : "2026-06-12T16:16:31Z"
  }
}