How severe is CVE-2021-34371?

CVE-2021-34371 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-34371 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34371?

CVE-2021-34371 affects Neo4j. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-34371?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-34371 published?

CVE-2021-34371 was published on 2021-08-05 and last updated on 2026-06-17.

CVE-2021-34371

CVE-2021-34371 is a critical-severity vulnerability in Neo4j with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 13% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 13% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Neo4j
Published: 2021-08-05
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-34371?: 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.
How severe is CVE-2021-34371?: CVE-2021-34371 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-34371 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34371?: CVE-2021-34371 affects Neo4j. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-34371?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-34371 published?: CVE-2021-34371 was published on 2021-08-05 and last updated on 2026-06-17.

References

https://www.exploit-db.com/exploits/50170

Affected products (1)

cpe:2.3:a:neo4j:neo4j:*:*:*:*:community:*:*:*

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