CVE-2021-43980: Apache Tomcat Apache Tomcat Race Condition Vulnerability Vulnerability

LOW
Advisory Identifier: GHSA-jx7c-7mj5-9438
Share
CVSS 3.7
CWE-362
Published
Advisory Summary

CVE-2021-43980 is a LOW (CVSS 3.7) apache tomcat race condition vulnerability vulnerability (CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')) affecting Apache Tomcat libraries in the Maven ecosystem. The issue involves apache tomcat race condition vulnerability. Remediation is available by upgrading affected packages to version 8.5.78, 9.0.62, 10.0.20, 10.1.0-M14.

CVE-2021-43980 at a Glance

CVE Identifier CVE-2021-43980
GHSA Identifier GHSA-jx7c-7mj5-9438
Severity LOW
CVSS v3.1 Base Score 3.7
CWE Classification CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Affected Product Apache Tomcat
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 3.7

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:N).

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 None (A:N)

How to Fix CVE-2021-43980

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: 8.5.78 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>8.5.78</version>
</dependency>
org.apache.tomcat:tomcat fixed: 9.0.62 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>9.0.62</version>
</dependency>
org.apache.tomcat:tomcat fixed: 10.0.20 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>10.0.20</version>
</dependency>
org.apache.tomcat:tomcat fixed: 10.1.0-M14 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>10.1.0-M14</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-2021-43980, 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 8.5.78), 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-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'), where the product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently. 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

The simplified implementation of blocking reads and writes introduced in Tomcat 10 and back-ported to Tomcat 9.0.47 onwards exposed a long standing (but extremely hard to trigger) concurrency bug in Apache Tomcat 10.1.0 to 10.1.0-M12, 10.0.0-M1 to 10.0.18, 9.0.0-M1 to 9.0.60 and 8.5.0 to 8.5.77 that could cause client connections to share an Http11Processor instance resulting in responses, or part responses, to be received by the wrong client.

CVE-2021-43980 Affected Apache Tomcat Versions

4 component(s)
Fixed Versions:
8.5.789.0.6210.0.2010.1.0-M14
Product / Package Ecosystem Affected Versions Fixed Version
org.apache.tomcat:tomcat
maven/org.apache.tomcat/tomcat
Maven
≥ 8.5.0
< 8.5.78
8.5.78
org.apache.tomcat:tomcat
maven/org.apache.tomcat/tomcat
Maven
≥ 9.0.0-M1
< 9.0.62
9.0.62
org.apache.tomcat:tomcat
maven/org.apache.tomcat/tomcat
Maven
≥ 10.0.0-M1
< 10.0.20
10.0.20
org.apache.tomcat:tomcat
maven/org.apache.tomcat/tomcat
Maven
≥ 10.1.0-M1
< 10.1.0-M14
10.1.0-M14

References

NVD — CVE-2021-43980 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-43980
Security Fix Commit FIX COMMIT
https://github.com/apache/tomcat/commit/170e0f792bd18ff031677890ba2fe50eb7a376c1
Security Fix Commit FIX COMMIT
https://github.com/apache/tomcat/commit/17f177eeb7df5938f67ef9ea580411b120195f13
Security Fix Commit FIX COMMIT
https://github.com/apache/tomcat/commit/4a00b0c0890538b9d3107eef8f2e0afadd119beb
Security Fix Commit FIX COMMIT
https://github.com/apache/tomcat/commit/9651b83a1d04583791525e5f0c4c9089f678d9fc
Apache Tomcat Source Repository REPOSITORY
https://github.com/apache/tomcat
lists.apache.org/thread/3jjqbsp6j88b... WEB
https://lists.apache.org/thread/3jjqbsp6j88b198x5rmg99b1qr8ht3g3
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2022/10/msg00029.html
Apache Tomcat Security Information SECURITY
https://tomcat.apache.org/security-10.html
Apache Tomcat Security Information SECURITY
https://tomcat.apache.org/security-8.html
Apache Tomcat Security Information SECURITY
https://tomcat.apache.org/security-9.html
Apache Tomcat Security Information SECURITY
https://www.debian.org/security/2022/dsa-5265
Apache Tomcat Security Information SECURITY
http://www.openwall.com/lists/oss-security/2022/09/28/1

Frequently Asked Questions

What is CVE-2021-43980?
CVE-2021-43980 is a security vulnerability in Apache Tomcat involving Apache Tomcat Race Condition vulnerability under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition').
Which Apache Tomcat versions are affected?
Affected versions include releases prior to 8.5.78, 9.0.62, 10.0.20, 10.1.0-M14 across affected packages: org.apache.tomcat:tomcat.
What version fixes CVE-2021-43980?
Upgrading to 8.5.78, 9.0.62, 10.0.20, 10.1.0-M14 (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 8.5.78, 9.0.62, 10.0.20, 10.1.0-M14. Upgrade your dependency to 8.5.78, 9.0.62, 10.0.20, 10.1.0-M14 or later.
What is the CVSS score of CVE-2021-43980?
CVE-2021-43980 has a CVSS v3.1 base score of 3.7 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2021-43980?
CVE-2021-43980 is classified under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') (The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.).
How can I check Maven dependencies for CVE-2021-43980?
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
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-jx7c-7mj5-9438",
  "modified" : "2024-03-11T16:38:56Z",
  "published" : "2022-09-29T00:00:25Z",
  "aliases" : [ "CVE-2021-43980" ],
  "summary" : "Apache Tomcat Race Condition vulnerability",
  "details" : "The simplified implementation of blocking reads and writes introduced in Tomcat 10 and back-ported to Tomcat 9.0.47 onwards exposed a long standing (but extremely hard to trigger) concurrency bug in Apache Tomcat 10.1.0 to 10.1.0-M12, 10.0.0-M1 to 10.0.18, 9.0.0-M1 to 9.0.60 and 8.5.0 to 8.5.77 that could cause client connections to share an Http11Processor instance resulting in responses, or part responses, to be received by the wrong client.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat:tomcat"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.5.0"
      }, {
        "fixed" : "8.5.78"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat:tomcat"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0-M1"
      }, {
        "fixed" : "9.0.62"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat:tomcat"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0-M1"
      }, {
        "fixed" : "10.0.20"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat:tomcat"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.1.0-M1"
      }, {
        "fixed" : "10.1.0-M14"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-43980"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/tomcat/commit/170e0f792bd18ff031677890ba2fe50eb7a376c1"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/tomcat/commit/17f177eeb7df5938f67ef9ea580411b120195f13"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/tomcat/commit/4a00b0c0890538b9d3107eef8f2e0afadd119beb"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/tomcat/commit/9651b83a1d04583791525e5f0c4c9089f678d9fc"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/apache/tomcat"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread/3jjqbsp6j88b198x5rmg99b1qr8ht3g3"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2022/10/msg00029.html"
  }, {
    "type" : "WEB",
    "url" : "https://tomcat.apache.org/security-10.html"
  }, {
    "type" : "WEB",
    "url" : "https://tomcat.apache.org/security-8.html"
  }, {
    "type" : "WEB",
    "url" : "https://tomcat.apache.org/security-9.html"
  }, {
    "type" : "WEB",
    "url" : "https://www.debian.org/security/2022/dsa-5265"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2022/09/28/1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-362" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-09-30T06:30:10Z",
    "nvd_published_at" : "2022-09-28T14:15:00Z"
  }
}