How severe is CVE-2018-1000820?

CVE-2018-1000820 has a CVSS score of 10/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2018-1000820?

CVE-2018-1000820 affects the following packages: org.neo4j.procedure:apoc (Maven). Ecosystems affected: Maven.

How do I fix CVE-2018-1000820?

Update org.neo4j.procedure:apoc to 3.4.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1000820 is resolved across your whole dependency graph.

How do I detect CVE-2018-1000820 in my Maven dependencies?

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

How do I mitigate CVE-2018-1000820 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2018-1000820 actively exploited in the wild?

No public exploit code has been indexed for CVE-2018-1000820 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2018-1000820?

CVE-2018-1000820 has an EPSS (Exploit Prediction Scoring System) score of 1.9%, placing it in the 79th 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 indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2018-1000820?

CVE-2018-1000820 is classified as XML External Entity (XXE) (CWE-611). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2018-1000820 published, and has it been updated?

CVE-2018-1000820 was published on December 20, 2018 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

CRITICAL severity

CVE-2018-1000820 — apoc

CRITICAL

CVE-2018-1000820 is a critical-severity (CVSS 10) XML External Entity (XXE) vulnerability in org.neo4j.procedure:apoc. A fix is available for org.neo4j.procedure:apoc — see the affected versions and patch details below.

XML External Entity (XXE) vulnerability in neo4j.procedure:apoc

Also known asGHSA-r2pp-x4mm-4999

Published

Dec 20, 2018

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs79th percentile — riskier than 79% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

☕org.neo4j.procedure:apoc

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-contrib neo4j-apoc-procedures version before commit 45bc09c contains a XML External Entity (XXE) vulnerability in XML Parser that can result in Disclosure of confidential data, denial of service, SSRF, port scanning. This vulnerability appears to have been fixed in after commit 45bc09c.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.neo4j.procedure:apoc`	all versions	3.4.0.4`org.neo4j.procedure:apoc:3.4.0.4`

Affected Products

1 product · 1 configurations

Application

awesome procedures on cyperneo4j

all

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.neo4j.procedure:apoc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.neo4j.procedure:apoc to 3.4.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1000820 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2018-1000820 in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

10/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Raw vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CWE Classification

CWE-611XML External Entity (XXE)

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

OpenSSF Scorecard

Package health score

neo4j-apoc-procedures

4.2/10

Code-Review4/10

Maintained5/10

Branch-Protection0/10

Assessed Nov 2, 2026

Timeline

Disclosed

Dec 20, 2018

Last updated

Oct 20, 2026

Identifiers

CVE-2018-1000820

GHSA-r2pp-x4mm-4999

References

Advisory0dd.zone · neo4f apoc procedures XXE Advisorynvd.nist.gov · CVE 2018 1000820 Fixgithub.com Web0dd.zone · neo4f apoc procedures XXE

Related vulnerabilities

Also affects apoc

This CVE is critical severity; 1 of 4 other CVEs affecting apoc is rated as high or higher (top: critical).

GHSA-9vx8-f5c4-862xCVE-2022-23532CVE-2022-37423CVE-2021-42767

Same weakness: CWE-611

This CVE is critical severity; 1 of 4 other CVEs with CWE-611 is rated as high or higher (top: critical).

CVE-2026-108358CVE-2026-108357CVE-2026-61586CVE-2026-61741Browse all CWE-611

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 20, 2026

CVE-2018-1000820 — apoc

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2018-1000820 in your dependencies?