CVE-2021-36161: Dubbo Remote Code Execution Vulnerability

CRITICAL
Advisory Identifier: GHSA-qvm7-23cj-437v
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CVSS 9.8
CWE-134
Published
Advisory Summary

CVE-2021-36161 is a CRITICAL (CVSS 9.8) remote code execution vulnerability (CWE-134: Use of Externally-Controlled Format String) affecting Dubbo libraries in the Maven ecosystem. The issue involves remote code execution in apache dubbo. Remediation is available by upgrading affected packages to version 2.7.13.

CVE-2021-36161 at a Glance

CVE Identifier CVE-2021-36161
GHSA Identifier GHSA-qvm7-23cj-437v
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-134: Use of Externally-Controlled Format String
Affected Product Dubbo
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.8

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:H/I:H/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 High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2021-36161

To remediate this vulnerability, upgrade all affected Dubbo 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.dubbo:dubbo fixed: 2.7.13 
<dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo</artifactId>
    <version>2.7.13</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.dubbo

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-36161, inspect your build dependencies using the Maven Dependency Plugin:

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

Analyze the terminal output to locate any version of Dubbo in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.7.13), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.apache.dubbo 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-134: Use of Externally-Controlled Format String, where the product uses a function that accepts a format string as an argument, but the format string originates from an external source. In Dubbo, 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

Some component in Dubbo will try to print the formated string of the input arguments, which will possibly cause RCE for a maliciously customized bean with special toString method. In the latest version, we fix the toString call in timeout, cache and some other places. Fixed in Apache Dubbo 2.7.13

CVE-2021-36161 Affected Dubbo Versions

1 component(s)
Fixed Versions:
2.7.13
Product / Package Ecosystem Affected Versions Fixed Version
org.apache.dubbo:dubbo
maven/org.apache.dubbo/dubbo
Maven
< 2.7.13
2.7.13

References

NVD — CVE-2021-36161 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-36161
Dubbo Source Repository REPOSITORY
https://github.com/apache/dubbo
lists.apache.org/thread.html/r402122... WEB
https://lists.apache.org/thread.html/r40212261fd5d638074b65f22ac73eebe93ace310c79d4cfcca4863da%40%3Cdev.dubbo.apache.org%3E

Frequently Asked Questions

What is CVE-2021-36161?
CVE-2021-36161 is a security vulnerability in Dubbo involving Remote Code Execution in Apache Dubbo under CWE-134: Use of Externally-Controlled Format String.
Which Dubbo versions are affected?
Affected versions include releases prior to 2.7.13 across affected packages: org.apache.dubbo:dubbo.
What version fixes CVE-2021-36161?
Upgrading to 2.7.13 (or the latest patched release for your respective branch) resolves the vulnerability.
Is dubbo affected?
Yes, org.apache.dubbo:dubbo is affected in releases prior to 2.7.13. Upgrade your dependency to 2.7.13 or later.
What is the CVSS score of CVE-2021-36161?
CVE-2021-36161 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2021-36161?
CVE-2021-36161 is classified under CWE-134: Use of Externally-Controlled Format String (The product uses a function that accepts a format string as an argument, but the format string originates from an external source.).
How can I check Maven dependencies for CVE-2021-36161?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.dubbo'. 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-qvm7-23cj-437v",
  "modified" : "2021-09-20T20:15:45Z",
  "published" : "2021-09-10T17:54:37Z",
  "aliases" : [ "CVE-2021-36161" ],
  "summary" : "Remote Code Execution in Apache Dubbo",
  "details" : "Some component in Dubbo will try to print the formated string of the input arguments, which will possibly cause RCE for a maliciously customized bean with special toString method. In the latest version, we fix the toString call in timeout, cache and some other places. Fixed in Apache Dubbo 2.7.13",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.dubbo:dubbo"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.7.13"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-36161"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/apache/dubbo"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r40212261fd5d638074b65f22ac73eebe93ace310c79d4cfcca4863da%40%3Cdev.dubbo.apache.org%3E"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-134" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-09-10T16:45:06Z",
    "nvd_published_at" : "2021-09-09T08:15:00Z"
  }
}