CVE-2021-34371: Neo4j Deserialization Of Untrusted Data Vulnerability

CRITICAL
Advisory Identifier: GHSA-pc4w-8v5j-29w9
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CVSS 9.8
CWE-502
Published
Advisory Summary

CVE-2021-34371 is a CRITICAL (CVSS 9.8) deserialization of untrusted data vulnerability (CWE-502: Deserialization of Untrusted Data) affecting Neo4j libraries in the Maven ecosystem. The issue involves deserialization of untrusted data in neo4j. Remediation is available by upgrading affected packages to version 3.5.0.

CVE-2021-34371 at a Glance

CVE Identifier CVE-2021-34371
GHSA Identifier GHSA-pc4w-8v5j-29w9
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-502: Deserialization of Untrusted Data
Affected Product Neo4j
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-2021-34371

To remediate this vulnerability, upgrade all affected Neo4j 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.neo4j:neo4j fixed: 3.5.0 
<dependency>
    <groupId>org.neo4j</groupId>
    <artifactId>neo4j</artifactId>
    <version>3.5.0</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.neo4j

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-34371, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.neo4j

Analyze the terminal output to locate any version of Neo4j in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.5.0), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.neo4j 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-502: Deserialization of Untrusted Data, where the product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. In Neo4j, 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

Neo4j through 3.4.18 (with the shell server enabled) exposes an RMI service that arbitrarily deserializes Java objects, e.g., through setSessionVariable. An attacker can abuse this for remote code execution because there are dependencies with exploitable gadget chains.

CVE-2021-34371 Affected Neo4j Versions

1 component(s)
Fixed Versions:
3.5.0
Product / Package Ecosystem Affected Versions Fixed Version
org.neo4j:neo4j
maven/org.neo4j/neo4j
Maven
< 3.5.0
3.5.0

References

NVD — CVE-2021-34371 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-34371
Neo4j Source Repository REPOSITORY
https://github.com/neo4j/neo4j
www.exploit-db.com/exploits/50170 WEB
https://www.exploit-db.com/exploits/50170

Frequently Asked Questions

What is CVE-2021-34371?
CVE-2021-34371 is a security vulnerability in Neo4j involving Deserialization of Untrusted Data in Neo4j under CWE-502: Deserialization of Untrusted Data.
Which Neo4j versions are affected?
Affected versions include releases prior to 3.5.0 across affected packages: org.neo4j:neo4j.
What version fixes CVE-2021-34371?
Upgrading to 3.5.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is neo4j affected?
Yes, org.neo4j:neo4j is affected in releases prior to 3.5.0. Upgrade your dependency to 3.5.0 or later.
What is the CVSS score of CVE-2021-34371?
CVE-2021-34371 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-2021-34371?
CVE-2021-34371 is classified under CWE-502: Deserialization of Untrusted Data (The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.).
How can I check Maven dependencies for CVE-2021-34371?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.neo4j'. 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-pc4w-8v5j-29w9",
  "modified" : "2021-08-30T21:46:09Z",
  "published" : "2021-09-01T18:31:29Z",
  "aliases" : [ "CVE-2021-34371" ],
  "summary" : "Deserialization of Untrusted Data in Neo4j",
  "details" : "Neo4j through 3.4.18 (with the shell server enabled) exposes an RMI service that arbitrarily deserializes Java objects, e.g., through setSessionVariable. An attacker can abuse this for remote code execution because there are dependencies with exploitable gadget chains.",
  "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.neo4j:neo4j"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.5.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-34371"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/neo4j/neo4j"
  }, {
    "type" : "WEB",
    "url" : "https://www.exploit-db.com/exploits/50170"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-502" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-30T21:46:09Z",
    "nvd_published_at" : "2021-08-05T20:15:00Z"
  }
}