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CRITICAL severity

GHSA-pc4w-8v5j-29w9

CRITICAL

GHSA-pc4w-8v5j-29w9 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in org.neo4j:neo4j. 3 public exploit references exist, so weaponization risk is real. O3 Security confirms whether GHSA-pc4w-8v5j-29w9 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Deserialization of Untrusted Data in Neo4j

Also known asBIT-neo4j-2021-34371CVE-2021-34371
Published
Sep 1, 2021
Updated
Dec 6, 2023
Affected
1 pkg
Patched
1 / 1
Exploits
3 known
Exploitation data as of Aug 23, 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

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-pc4w-8v5j-29w9 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 365,017 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
org.neo4j:neo4j

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven 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
EcosystemPackageVulnerable rangeFix
Mavenorg.neo4j:neo4jall versions3.5.0
Exploits & PoCs
3

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

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.neo4j:neo4j. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update org.neo4j:neo4j to 3.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pc4w-8v5j-29w9 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-pc4w-8v5j-29w9 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-pc4w-8v5j-29w9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

Is GHSA-pc4w-8v5j-29w9 in your dependencies?

O3 detects GHSA-pc4w-8v5j-29w9 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

GHSA-pc4w-8v5j-29w9: Deserialization of… | O3 Security