CVE-2021-30181: Dubbo Code Injection Vulnerability

CRITICAL
Advisory Identifier: GHSA-qmfc-6www-fjqw
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CVSS 9.8
CWE-94
Published
Advisory Summary

CVE-2021-30181 is a CRITICAL (CVSS 9.8) code injection vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Dubbo libraries in the Maven ecosystem. The issue involves code injection in apache dubbo. Remediation is available by upgrading affected packages to version 2.6.9, 2.7.10.

CVE-2021-30181 at a Glance

CVE Identifier CVE-2021-30181
GHSA Identifier GHSA-qmfc-6www-fjqw
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')
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-2021-30181

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.

com.alibaba:dubbo fixed: 2.6.9 
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>dubbo</artifactId>
    <version>2.6.9</version>
</dependency>
org.apache.dubbo:dubbo fixed: 2.7.10 
<dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo</artifactId>
    <version>2.7.10</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=com.alibaba

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-30181, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=com.alibaba

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 2.6.9), your application is affected.

Note: The mvn dependency:tree -Dincludes=com.alibaba 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-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. 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 prior to 2.6.9 and 2.7.10 supports Script routing which will enable a customer to route the request to the right server. These rules are used by the customers when making a request in order to find the right endpoint. When parsing these rules, Dubbo customers use ScriptEngine and run the rule provided by the script which by default may enable executing arbitrary code.

CVE-2021-30181 Affected Dubbo Versions

2 component(s)
Fixed Versions:
2.6.92.7.10
Product / Package Ecosystem Affected Versions Fixed Version
com.alibaba:dubbo
maven/com.alibaba/dubbo
Maven
≥ 2.5.0
< 2.6.9
2.6.9
org.apache.dubbo:dubbo
maven/org.apache.dubbo/dubbo
Maven
≥ 2.5.0
< 2.7.10
2.7.10

References

NVD — CVE-2021-30181 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-30181
lists.apache.org/thread.html/re22410... WEB
https://lists.apache.org/thread.html/re22410dc704a09bc7032ddf15140cf5e7df3e8ece390fc9032ff5587%40%3Cdev.dubbo.apache.org%3E

Frequently Asked Questions

What is CVE-2021-30181?
CVE-2021-30181 is a security vulnerability in Dubbo involving Code injection in Apache Dubbo under CWE-94: Improper Control of Generation of Code ('Code Injection').
Which Dubbo versions are affected?
Affected versions include releases prior to 2.6.9, 2.7.10 across affected packages: com.alibaba:dubbo, org.apache.dubbo:dubbo.
What version fixes CVE-2021-30181?
Upgrading to 2.6.9, 2.7.10 (or the latest patched release for your respective branch) resolves the vulnerability.
Is dubbo affected?
Yes, com.alibaba:dubbo is affected in releases prior to 2.6.9, 2.7.10. Upgrade your dependency to 2.6.9, 2.7.10 or later.
What is the CVSS score of CVE-2021-30181?
CVE-2021-30181 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-2021-30181?
CVE-2021-30181 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).
How can I check Maven dependencies for CVE-2021-30181?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=com.alibaba'. 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-qmfc-6www-fjqw",
  "modified" : "2022-03-18T17:57:04Z",
  "published" : "2022-03-18T17:57:04Z",
  "aliases" : [ "CVE-2021-30181" ],
  "summary" : "Code injection in Apache Dubbo",
  "details" : "Apache Dubbo prior to 2.6.9 and 2.7.10 supports Script routing which will enable a customer to route the request to the right server. These rules are used by the customers when making a request in order to find the right endpoint. When parsing these rules, Dubbo customers use ScriptEngine and run the rule provided by the script which by default may enable executing arbitrary code.",
  "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" : "com.alibaba:dubbo"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.5.0"
      }, {
        "fixed" : "2.6.9"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.dubbo:dubbo"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.5.0"
      }, {
        "fixed" : "2.7.10"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-30181"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/re22410dc704a09bc7032ddf15140cf5e7df3e8ece390fc9032ff5587%40%3Cdev.dubbo.apache.org%3E"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-06-02T20:15:20Z",
    "nvd_published_at" : "2021-06-01T14:15:00Z"
  }
}