How severe is CVE-2021-34371?

No CVSS score has been assigned to CVE-2021-34371 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2021-34371?

CVE-2021-34371 affects the following packages: neo4j (Bitnami). Ecosystems affected: Bitnami.

How do I fix CVE-2021-34371?

Update neo4j to 3.4.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-34371 is resolved across your whole dependency graph.

How do I detect CVE-2021-34371 in my Bitnami dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for neo4j, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-34371 if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Is CVE-2021-34371 actively exploited in the wild?

Yes. There are 3 known exploit references for CVE-2021-34371, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-34371?

CVE-2021-34371 has an EPSS (Exploit Prediction Scoring System) score of 13.4%, placing it in the 96th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

What type of vulnerability is CVE-2021-34371?

CVE-2021-34371 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-34371 published, and has it been updated?

CVE-2021-34371 was published on March 6, 2024 and was last updated on September 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 Bitnami

Not in CISA KEV

CVE-2021-34371 — neo4j

CVE-2021-34371 is a Deserialization of Untrusted Data vulnerability in neo4j. 3 public exploit references exist, so weaponization risk is real. A fix is available for neo4j — see the affected versions and patch details below.

Also known asBIT-neo4j-enterprise-2021-34371GHSA-pc4w-8v5j-29w9

Published

Mar 6, 2024

Updated

Sep 8, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

3 known

Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

13.4%probability of exploitation in next 30 days

Moderate Risk0.00%

Lower risk than most CVEs96th percentile — riskier than 96% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

📦neo4j

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Bitnami packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦Bitnami	`neo4j`	all versions	3.4.19

Affected Products

1 product · 1 configurations

Application

neo4jneo4j

≤ 3.4.18

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Neo4j through 3.4.18 (with the shell server enabled) exposes an RMI serv…

exploit-db.comNVDAug 2021

Neo4j through 3.4.18 (with the shell server enabled) exposes an RMI serv…

github.comGithubSep 2021

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for neo4j, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update neo4j to 3.4.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-34371 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-34371 in your dependencies?

Find it across Bitnami, including transitive dependencies.

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