CVE-2021-36162: Dubbo Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-r577-4hq7-73qh
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CVSS 8.8
CWE-77
Published
Advisory Summary

CVE-2021-36162 is a HIGH (CVSS 8.8) remote code execution vulnerability (CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')) 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, 3.0.2.

CVE-2021-36162 at a Glance

CVE Identifier CVE-2021-36162
GHSA Identifier GHSA-r577-4hq7-73qh
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')
Affected Product Dubbo
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
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-2021-36162

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>
org.apache.dubbo:dubbo fixed: 3.0.2 
<dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo</artifactId>
    <version>3.0.2</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-2021-36162, 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-77: Improper Neutralization of Special Elements used in a Command ('Command Injection'), where the product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. 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

Apache Dubbo supports various rules to support configuration override or traffic routing (called routing in Dubbo). These rules are loaded into the configuration center (eg: Zookeeper, Nacos, ...) and retrieved by the customers when making a request in order to find the right endpoint. When parsing these YAML rules, Dubbo customers will use SnakeYAML library to load the rules which by default will enable calling arbitrary constructors. An attacker with access to the configuration center he will be able to poison the rule so when retrieved by the consumers, it will get RCE on all of them. This was fixed in Dubbo 2.7.13, 3.0.2

CVE-2021-36162 Affected Dubbo Versions

2 component(s)
Fixed Versions:
2.7.133.0.2
Product / Package Ecosystem Affected Versions Fixed Version
org.apache.dubbo:dubbo
maven/org.apache.dubbo/dubbo
Maven
< 2.7.13
2.7.13
org.apache.dubbo:dubbo
maven/org.apache.dubbo/dubbo
Maven
≥ 3.0.0
< 3.0.2
3.0.2

References

NVD — CVE-2021-36162 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-36162
Dubbo Source Repository REPOSITORY
https://github.com/apache/dubbo
lists.apache.org/thread.html/rfa3511... WEB
https://lists.apache.org/thread.html/rfa351115a459e214b99ffcc52c35f33359f3370c547d9c6ba1a60037%40%3Cdev.dubbo.apache.org%3E

Frequently Asked Questions

What is CVE-2021-36162?
CVE-2021-36162 is a security vulnerability in Dubbo involving Remote Code Execution in Apache Dubbo under CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection').
Which Dubbo versions are affected?
Affected versions include releases prior to 2.7.13, 3.0.2 across affected packages: org.apache.dubbo:dubbo.
What version fixes CVE-2021-36162?
Upgrading to 2.7.13, 3.0.2 (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, 3.0.2. Upgrade your dependency to 2.7.13, 3.0.2 or later.
What is the CVSS score of CVE-2021-36162?
CVE-2021-36162 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2021-36162?
CVE-2021-36162 is classified under CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection') (The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.).
How can I check Maven dependencies for CVE-2021-36162?
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-r577-4hq7-73qh",
  "modified" : "2021-09-15T18:29:18Z",
  "published" : "2021-09-08T20:14:24Z",
  "aliases" : [ "CVE-2021-36162" ],
  "summary" : "Remote Code Execution in Apache Dubbo",
  "details" : "Apache Dubbo supports various rules to support configuration override or traffic routing (called routing in Dubbo). These rules are loaded into the configuration center (eg: Zookeeper, Nacos, ...) and retrieved by the customers when making a request in order to find the right endpoint. When parsing these YAML rules, Dubbo customers will use SnakeYAML library to load the rules which by default will enable calling arbitrary constructors. An attacker with access to the configuration center he will be able to poison the rule so when retrieved by the consumers, it will get RCE on all of them. This was fixed in Dubbo 2.7.13, 3.0.2",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/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"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.dubbo:dubbo"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0"
      }, {
        "fixed" : "3.0.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-36162"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/apache/dubbo"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/rfa351115a459e214b99ffcc52c35f33359f3370c547d9c6ba1a60037%40%3Cdev.dubbo.apache.org%3E"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-77" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-09-08T17:55:48Z",
    "nvd_published_at" : "2021-09-07T10:15:00Z"
  }
}