CVE-2020-7238: Netty handler HTTP Request Smuggling Vulnerability

HIGH
Advisory Identifier: GHSA-ff2w-cq2g-wv5f
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CVSS 7.5
CWE-444
Published
Advisory Summary

CVE-2020-7238 is a HIGH (CVSS 7.5) http request smuggling vulnerability (CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')) affecting Netty handler libraries in the Maven ecosystem. The issue involves http request smuggling in netty. Remediation is available by upgrading affected packages to version 4.1.45.

CVE-2020-7238 at a Glance

CVE Identifier CVE-2020-7238
GHSA Identifier GHSA-ff2w-cq2g-wv5f
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Product Netty handler
Package Ecosystem Maven
Published Date
Last Updated

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:H/A:N).

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 High (I:H)
Availability None (A:N)

How to Fix CVE-2020-7238

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: 4.1.45 
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-handler</artifactId>
    <version>4.1.45</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-2020-7238, 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 4.1.45), 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-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling'), where the product acts as an intermediary http agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed http requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. 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

Netty 4.1.43.Final allows HTTP Request Smuggling because it mishandles Transfer-Encoding whitespace (such as a [space]Transfer-Encoding:chunked line) and a later Content-Length header. This issue exists because of an incomplete fix for CVE-2019-16869.

CVE-2020-7238 Affected Netty handler Versions

1 component(s)
Fixed Versions:
4.1.45
Product / Package Ecosystem Affected Versions Fixed Version
io.netty:netty-handler
maven/io.netty/netty-handler
Maven
≥ 4.1.43
< 4.1.45
4.1.45

References

NVD — CVE-2020-7238 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-7238
Netty handler Source Repository REPOSITORY
https://github.com/jdordonezn/CVE-2020-72381/issues/1
Netty handler Source Repository REPOSITORY
https://github.com/netty/netty/issues/9861
Netty handler Source Repository REPOSITORY
https://github.com/netty/netty/pull/9865
Netty handler Security Information SECURITY
https://www.debian.org/security/2021/dsa-4885
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TS6VX7OMXPDJIU5LRGUAHRK6MENAVJ46
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2020/09/msg00003.html
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2020/02/msg00018.html
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2020/02/msg00017.html
lists.apache.org/thread.html/rc8d554... WEB
https://lists.apache.org/thread.html/rc8d554aad889d12b140d9fd7d2d6fc2e8716e9792f6f4e4b2cdc2d05@%3Ccommits.cassandra.apache.org%3E
lists.apache.org/thread.html/r131e57... WEB
https://lists.apache.org/thread.html/r131e572d003914843552fa45c4398b9903fb74144986e8b107c0a3a7@%3Ccommits.cassandra.apache.org%3E
access.redhat.com/errata/rhsa-2020:08... WEB
https://access.redhat.com/errata/RHSA-2020:0811
access.redhat.com/errata/rhsa-2020:08... WEB
https://access.redhat.com/errata/RHSA-2020:0806
access.redhat.com/errata/rhsa-2020:08... WEB
https://access.redhat.com/errata/RHSA-2020:0805
access.redhat.com/errata/rhsa-2020:08... WEB
https://access.redhat.com/errata/RHSA-2020:0804
access.redhat.com/errata/rhsa-2020:06... WEB
https://access.redhat.com/errata/RHSA-2020:0606
access.redhat.com/errata/rhsa-2020:06... WEB
https://access.redhat.com/errata/RHSA-2020:0605
access.redhat.com/errata/rhsa-2020:06... WEB
https://access.redhat.com/errata/RHSA-2020:0601
access.redhat.com/errata/rhsa-2020:05... WEB
https://access.redhat.com/errata/RHSA-2020:0567
access.redhat.com/errata/rhsa-2020:04... WEB
https://access.redhat.com/errata/RHSA-2020:0497
netty.io/news WEB
https://netty.io/news

Frequently Asked Questions

What is CVE-2020-7238?
CVE-2020-7238 is a security vulnerability in Netty handler involving HTTP Request Smuggling in Netty under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling').
Which Netty handler versions are affected?
Affected versions include releases prior to 4.1.45 across affected packages: io.netty:netty-handler.
What version fixes CVE-2020-7238?
Upgrading to 4.1.45 (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 4.1.45. Upgrade your dependency to 4.1.45 or later.
What is the CVSS score of CVE-2020-7238?
CVE-2020-7238 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:H/A:N.
What CWE is associated with CVE-2020-7238?
CVE-2020-7238 is classified under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') (The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.).
How can I check Maven dependencies for CVE-2020-7238?
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-ff2w-cq2g-wv5f",
  "modified" : "2021-08-19T17:32:40Z",
  "published" : "2020-02-21T18:55:50Z",
  "aliases" : [ "CVE-2020-7238" ],
  "summary" : "HTTP Request Smuggling in Netty",
  "details" : "Netty 4.1.43.Final allows HTTP Request Smuggling because it mishandles Transfer-Encoding whitespace (such as a [space]Transfer-Encoding:chunked line) and a later Content-Length header. This issue exists because of an incomplete fix for CVE-2019-16869.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
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    },
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        "introduced" : "4.1.43"
      }, {
        "fixed" : "4.1.45"
      } ]
    } ],
    "database_specific" : {
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    }
  } ],
  "references" : [ {
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    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-7238"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/jdordonezn/CVE-2020-72381/issues/1"
  }, {
    "type" : "WEB",
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  }, {
    "type" : "WEB",
    "url" : "https://github.com/netty/netty/pull/9865"
  }, {
    "type" : "WEB",
    "url" : "https://www.debian.org/security/2021/dsa-4885"
  }, {
    "type" : "WEB",
    "url" : "https://netty.io/news"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TS6VX7OMXPDJIU5LRGUAHRK6MENAVJ46"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2020/09/msg00003.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2020/02/msg00018.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2020/02/msg00017.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rc8d554aad889d12b140d9fd7d2d6fc2e8716e9792f6f4e4b2cdc2d05@%3Ccommits.cassandra.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r131e572d003914843552fa45c4398b9903fb74144986e8b107c0a3a7@%3Ccommits.cassandra.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0811"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0806"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0805"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0804"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0606"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0605"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0601"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0567"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0497"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-444" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-02-20T20:54:49Z",
    "nvd_published_at" : "2020-01-27T17:15:00Z"
  }
}