CVE-2021-41079: Apache Tomcat Infinite Loop Vulnerability

HIGH
Advisory Identifier: GHSA-59g9-7gfx-c72p
CVSS 7.5
CWE-20 CWE-835
Published
Advisory Summary

CVE-2021-41079 is a HIGH (CVSS 7.5) infinite loop vulnerability (CWE-20: Improper Input Validation) affecting Apache Tomcat libraries in the Maven ecosystem. The issue involves infinite loop in tomcat due to parsing error. Remediation is available by upgrading affected packages to version 10.0.4, 9.0.44, 8.5.64.

CVE-2021-41079 at a Glance

CVE Identifier CVE-2021-41079
GHSA Identifier GHSA-59g9-7gfx-c72p
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-20: Improper Input Validation
Affected Product Apache Tomcat
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: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-2021-41079

To remediate this vulnerability, upgrade all affected Apache Tomcat dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.apache.tomcat:tomcat fixed: 10.0.4
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>10.0.4</version>
</dependency>
org.apache.tomcat:tomcat fixed: 9.0.44
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>9.0.44</version>
</dependency>
org.apache.tomcat:tomcat fixed: 8.5.64
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>8.5.64</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=org.apache.tomcat

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-41079, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.apache.tomcat

Analyze the terminal output to locate any version of Apache Tomcat in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 10.0.4), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.apache.tomcat 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-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In Apache Tomcat, 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

Apache Tomcat 8.5.0 to 8.5.63, 9.0.0-M1 to 9.0.43 and 10.0.0-M1 to 10.0.2 did not properly validate incoming TLS packets. When Tomcat was configured to use NIO+OpenSSL or NIO2+OpenSSL for TLS, a specially crafted packet could be used to trigger an infinite loop resulting in a denial of service.

CVE-2021-41079 Affected Apache Tomcat Versions

3 component(s)
Fixed Versions:
10.0.49.0.448.5.64
Product / Package Ecosystem Affected Versions Fixed Version
org.apache.tomcat:tomcat
Maven
≥ 10.0.0
< 10.0.4
10.0.4
org.apache.tomcat:tomcat
Maven
≥ 9.0.0
< 9.0.44
9.0.44
org.apache.tomcat:tomcat
Maven
≥ 8.5.0
< 8.5.64
8.5.64

References

Frequently Asked Questions

What is CVE-2021-41079?
CVE-2021-41079 is a security vulnerability in Apache Tomcat involving Infinite loop in Tomcat due to parsing error under CWE-20: Improper Input Validation.
Which Apache Tomcat versions are affected?
Affected versions include releases prior to 10.0.4, 9.0.44, 8.5.64 across affected packages: org.apache.tomcat:tomcat.
What version fixes CVE-2021-41079?
Upgrading to 10.0.4, 9.0.44, 8.5.64 (or the latest patched release for your respective branch) resolves the vulnerability.
Is tomcat affected?
Yes, org.apache.tomcat:tomcat is affected in releases prior to 10.0.4, 9.0.44, 8.5.64. Upgrade your dependency to 10.0.4, 9.0.44, 8.5.64 or later.
What is the CVSS score of CVE-2021-41079?
CVE-2021-41079 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-2021-41079?
CVE-2021-41079 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check Maven dependencies for CVE-2021-41079?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.tomcat'. 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
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-59g9-7gfx-c72p",
  "modified" : "2021-10-18T14:52:03Z",
  "published" : "2021-09-20T20:45:44Z",
  "aliases" : [ "CVE-2021-41079" ],
  "summary" : "Infinite loop in Tomcat due to parsing error",
  "details" : "Apache Tomcat 8.5.0 to 8.5.63, 9.0.0-M1 to 9.0.43 and 10.0.0-M1 to 10.0.2 did not properly validate incoming TLS packets. When Tomcat was configured to use NIO+OpenSSL or NIO2+OpenSSL for TLS, a specially crafted packet could be used to trigger an infinite loop resulting in a denial of service.",
  "severity" : [ {
    "type" : "CVSS_V3",
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  } ],
  "references" : [ {
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  }, {
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    "url" : "https://github.com/apache/tomcat/commit/34115fb3c83f6cd97772232316a492a4cc5729e0"
  }, {
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    "url" : "https://github.com/apache/tomcat"
  }, {
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    "url" : "https://lists.apache.org/thread.html/r6b6b674e3f168dd010e67dbe6848b866e2acf26371452fdae313b98a@%3Cusers.tomcat.apache.org%3E"
  }, {
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  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rccdef0349fdf4fb73a4e4403095446d7fe6264e0a58e2df5c6799434%40%3Cannounce.tomcat.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2021/09/msg00012.html"
  }, {
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    "url" : "https://security.netapp.com/advisory/ntap-20211008-0005"
  }, {
    "type" : "WEB",
    "url" : "https://www.debian.org/security/2021/dsa-4986"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20", "CWE-835" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-09-17T18:01:45Z",
    "nvd_published_at" : "2021-09-16T15:15:00Z"
  }
}