Cyber Resilience

CVE-2018-20434

RCE in Librenms 1.46

Public PoCHigh EPSSRCECommand Injection
Published
24 April 2019
Modified
21 November 2024
CVSS Score v3 9.8
Click a component to see what it means
Raw vectorCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.71 99.4th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2018-20434 is a critical-severity OS Command Injection (CWE-78) vulnerability in Librenms Librenms. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 0.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

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.

CWE(s)
CWE-78

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1190 Exploit Public-Facing Application Initial Accessconfidence: HIGH
The CVE describes unauthenticated remote command execution via a web application endpoint (addhost.inc.php), directly enabling exploitation of a public-facing application.
attack.mitre.org →
T1059.004 Unix Shell Executionconfidence: HIGH
The vulnerability allows injection of arbitrary OS commands that are executed via the Unix shell on the target system.
attack.mitre.org →
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-6204Same product: Librenms Librenms
CVE-2024-51092Same product: Librenms Librenms
CVE-2025-65093Same product: Librenms Librenms
CVE-2026-26991Same product: Librenms Librenms
CVE-2024-53457Same product: Librenms Librenms
CVE-2023-5060Same product: Librenms Librenms
CVE-2023-48295Same product: Librenms Librenms
CVE-2024-51497Same product: Librenms Librenms
CVE-2024-47523Same product: Librenms Librenms
CVE-2024-50355Same product: Librenms Librenms

Affected Assets

librenms
librenms
1.46

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.2.5
  • V1.2.8
  • V15.2.5

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-27 Platform-independent Applications
addresses: CWE-78

Platform-independent apps typically execute inside a managed runtime or sandbox that restricts direct OS command execution, reducing the ability to exploit OS command injection.

SI-10 Information Input Validation
addresses: CWE-78

Validates inputs to block special elements that would alter OS command execution.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.

PR.PS-02 partial match
prevents

Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.

References