CVE-2016-4970: Netty handler Loop With Unreachable Exit Condition Vulnerability

Q: What is CVE-2016-4970?

CVE-2016-4970 is a security vulnerability in Netty handler involving Loop with Unreachable Exit Condition in Netty under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop').

Q: Which Netty handler versions are affected?

Affected versions include releases prior to 4.0.37.Final, 4.1.1.Final across affected packages: io.netty:netty-handler.

Q: What version fixes CVE-2016-4970?

Upgrading to 4.0.37.Final, 4.1.1.Final (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is netty-handler affected?

Yes, io.netty:netty-handler is affected in releases prior to 4.0.37.Final, 4.1.1.Final. Upgrade your dependency to 4.0.37.Final, 4.1.1.Final or later.

Q: What is the CVSS score of CVE-2016-4970?

CVE-2016-4970 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Q: What CWE is associated with CVE-2016-4970?

CVE-2016-4970 is classified under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') (The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.).

Q: How can I check Maven dependencies for CVE-2016-4970?

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.

HIGH

Advisory Identifier: GHSA-rv63-gqm8-9w8q

CVSS 7.5

CWE-835

Published 2022-05-13

Advisory Summary

CVE-2016-4970 is a HIGH (CVSS 7.5) loop with unreachable exit condition vulnerability (CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')) affecting Netty handler libraries in the Maven ecosystem. The issue involves loop with unreachable exit condition in netty. Remediation is available by upgrading affected packages to version 4.0.37.Final, 4.1.1.Final.

CVE-2016-4970 at a Glance

CVE Identifier CVE-2016-4970

GHSA Identifier GHSA-rv63-gqm8-9w8q

Severity HIGH

CVSS v3.1 Base Score 7.5

CWE Classification CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')

Affected Product Netty handler

Package Ecosystem Maven

Published Date 2022-05-13

Last Updated 2022-07-06

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).

Attack Vector Network (AV:N)

Attack Complexity Low (AC:L)

Privileges Required None (PR:N)

User Interaction None (UI:N)

Scope Unchanged (S:U)

Confidentiality None (C:N)

Integrity None (I:N)

Availability High (A:H)

How to Fix CVE-2016-4970

To remediate this vulnerability, upgrade all affected Netty handler 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-handler fixed: 4.0.37.Final

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-handler</artifactId>
    <version>4.0.37.Final</version>
</dependency>

io.netty:netty-handler fixed: 4.1.1.Final

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-handler</artifactId>
    <version>4.1.1.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-2016-4970, 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 handler in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.0.37.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-835: Loop with Unreachable Exit Condition ('Infinite Loop'), where the product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. In Netty handler, 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

handler/ssl/OpenSslEngine.java in Netty 4.0.x before 4.0.37.Final and 4.1.x before 4.1.1.Final allows remote attackers to cause a denial of service (infinite loop).

CVE-2016-4970 Affected Netty handler Versions

2 component(s)

Fixed Versions:

4.0.37.Final4.1.1.Final

Product / Package	Ecosystem	Affected Versions	Fixed Version
io.netty:netty-handler maven/io.netty/netty-handler	Maven	≥ 4.0.0.Alpha1 < 4.0.37.Final	4.0.37.Final
io.netty:netty-handler maven/io.netty/netty-handler	Maven	≥ 4.1.0.Beta1 < 4.1.1.Final	4.1.1.Final

References

NVD — CVE-2016-4970 NVD

https://nvd.nist.gov/vuln/detail/CVE-2016-4970

Netty handler Source Repository REPOSITORY

https://github.com/netty/netty/pull/5364

bugzilla.redhat.com/show_bug.cgi WEB

https://bugzilla.redhat.com/show_bug.cgi?id=1343616

Netty handler Source Repository REPOSITORY

https://github.com/netty/netty

lists.apache.org/thread.html/afaa586... WEB

https://lists.apache.org/thread.html/afaa5860e3a6d327eb96c3d82cbd2f5996de815a16854ed1ad310144@%3Ccommits.cassandra.apache.org%3E

Netty handler Security Information SECURITY

https://wiki.opendaylight.org/view/Security_Advisories

netty.io/news/2016/06/07/4-0... WEB

http://netty.io/news/2016/06/07/4-0-37-Final.html

netty.io/news/2016/06/07/4-1... WEB

http://netty.io/news/2016/06/07/4-1-1-Final.html

rhn.redhat.com/errata/rhsa-2017-01... WEB

http://rhn.redhat.com/errata/RHSA-2017-0179.html

rhn.redhat.com/errata/rhsa-2017-10... WEB

http://rhn.redhat.com/errata/RHSA-2017-1097.html

Frequently Asked Questions

What is CVE-2016-4970?

CVE-2016-4970 is a security vulnerability in Netty handler involving Loop with Unreachable Exit Condition in Netty under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop').

Which Netty handler versions are affected?

Affected versions include releases prior to 4.0.37.Final, 4.1.1.Final across affected packages: io.netty:netty-handler.

What version fixes CVE-2016-4970?

Upgrading to 4.0.37.Final, 4.1.1.Final (or the latest patched release for your respective branch) resolves the vulnerability.

Is netty-handler affected?

Yes, io.netty:netty-handler is affected in releases prior to 4.0.37.Final, 4.1.1.Final. Upgrade your dependency to 4.0.37.Final, 4.1.1.Final or later.

What is the CVSS score of CVE-2016-4970?

CVE-2016-4970 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

What CWE is associated with CVE-2016-4970?

CVE-2016-4970 is classified under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') (The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.).

How can I check Maven dependencies for CVE-2016-4970?

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-rv63-gqm8-9w8q",
  "modified" : "2022-07-06T19:54:08Z",
  "published" : "2022-05-13T01:11:43Z",
  "aliases" : [ "CVE-2016-4970" ],
  "summary" : "Loop with Unreachable Exit Condition in Netty",
  "details" : "handler/ssl/OpenSslEngine.java in Netty 4.0.x before 4.0.37.Final and 4.1.x before 4.1.1.Final allows remote attackers to cause a denial of service (infinite loop).",
  "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-handler"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0.Alpha1"
      }, {
        "fixed" : "4.0.37.Final"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "io.netty:netty-handler"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.1.0.Beta1"
      }, {
        "fixed" : "4.1.1.Final"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2016-4970"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/netty/netty/pull/5364"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1343616"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/netty/netty"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/afaa5860e3a6d327eb96c3d82cbd2f5996de815a16854ed1ad310144@%3Ccommits.cassandra.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://wiki.opendaylight.org/view/Security_Advisories"
  }, {
    "type" : "WEB",
    "url" : "http://netty.io/news/2016/06/07/4-0-37-Final.html"
  }, {
    "type" : "WEB",
    "url" : "http://netty.io/news/2016/06/07/4-1-1-Final.html"
  }, {
    "type" : "WEB",
    "url" : "http://rhn.redhat.com/errata/RHSA-2017-0179.html"
  }, {
    "type" : "WEB",
    "url" : "http://rhn.redhat.com/errata/RHSA-2017-1097.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-835" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-07-06T19:54:08Z",
    "nvd_published_at" : "2017-04-13T14:59:00Z"
  }
}

CVSS V3

7.5 HIGH