How severe is CVE-2018-20434?

CVE-2018-20434 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2018-20434?

CVE-2018-20434 affects the following packages: librenms/librenms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2018-20434?

The records we use list no patched version of librenms/librenms for CVE-2018-20434. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

How do I detect CVE-2018-20434 in my Packagist dependencies?

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

How do I mitigate CVE-2018-20434 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2018-20434 actively exploited in the wild?

Yes. There are 7 known exploit references for CVE-2018-20434, including 2 documented proof-of-concept exploits on Exploit-DB and 4 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-2018-20434?

CVE-2018-20434 has an EPSS (Exploit Prediction Scoring System) score of 71.5%, placing it in the 99th 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. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2018-20434?

CVE-2018-20434 is classified as OS Command Injection (CWE-78). 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.

Is there exploit tooling available for CVE-2018-20434?

A Metasploit module references CVE-2018-20434, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2018-20434 published, and has it been updated?

CVE-2018-20434 was published on April 24, 2019 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

CRITICAL severity

CVE-2018-20434 — librenms

CRITICAL

CVE-2018-20434 is a critical-severity (CVSS 9.8) OS Command Injection vulnerability in librenms/librenms. 7 public exploit or proof-of-concept references are indexed, so weaponization risk is real. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

LibreNMS arbitrary OS commands execution

Also known asGHSA-62q7-qj6g-gvr7

Published

Apr 24, 2019

Updated

Oct 24, 2026

Affected

1 pkg

Patched

See advisory

Exploits

7 known

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

71.5%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs99th percentile — riskier than 99% 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

🐘librenms/librenms

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

Description

LibreNMS 1.46 allows remote attackers to execute arbitrary OS commands by using the $_POST['community'] parameter to html/pages/addhost.inc.php during creation of a new device, and then making a /ajax_output.php?id=capture&format=text&type=snmpwalk&hostname=localhost request that triggers html/includes/output/capture.inc.php command mishandling.

Affected Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`librenms/librenms`	all versions	No fix

Affected Products

1 product · 1 configurations

Application

librenmslibrenms

1 version

1.46

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.

EDB-47044webappsphp✓ Verified

LibreNMS 1.46 - 'addhost' Remote Code Execution

by Askar · Jun 28, 2019

Exploit-DB Source

EDB-46970remotelinux✓ Verified

LibreNMS - addhost Command Injection (Metasploit)

by Metasploit · Jun 5, 2019

Exploit-DB Source

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for librenms/librenms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of librenms/librenms for CVE-2018-20434. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
Mitigate without a patch
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2018-20434 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works