CVE-2021-34371Public exploitNetwork attack vector

Unauthenticated code execution via RMI object deserialization

Published Aug 5, 2021 · Updated Aug 4, 2024

Unsafe deserialization in Neo4j through 3.4.18 allows remote attackers to execute code through an enabled shell server RMI service. The setSessionVariable method accepts an Object over RMI and deserializes it without restricting attacker-controlled classes, allowing the bundled Rhino 1.7.9 gadget chain to invoke operating-system commands. The shell server must be enabled and network-reachable; successful exploitation runs arbitrary commands with the Neo4j process privileges.

CVSS severity9.8
Critical
EPSS probability13.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in Neo4j through 3.4.18 allows remote attackers to execute code through an enabled shell server RMI service. The setSessionVariable method accepts an Object over RMI and deserializes it without restricting attacker-controlled classes, allowing the bundled Rhino 1.7.9 gadget chain to invoke operating-system commands. The shell server must be enabled and network-reachable; successful exploitation runs arbitrary commands with the Neo4j process privileges.

The record

CVE
CVE-2021-34371
Published
Aug 5, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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