CVE-2018-20434

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this weekWeaponized
9.8
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 71%
CISA-KEV: Not listedEPSS: 71%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
77(Track*)
EG Risk 77/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation71% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
99.4%
KEV
Not listed

Published

April 24, 2019

Last Modified

November 21, 2024

Advisory Details (3)

Auto-updated Jul 10, 2026
No patch confirmed yet.
generic

LibreNMS v1.46 Remote Code Execution (CVE-2018-20434) // Askar

https://shells.systems/librenms-v1-46-remote-code-execution-cve-2018-20434/
generic

librenms-exploit.py · GitHub

https://gist.github.com/mhaskar/516df57aafd8c6e3a1d70765075d372d
generic

Packet Storm Security

http://packetstormsecurity.com/files/153188/LibreNMS-addhost-Command-Injection.html

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
composerlibrenms/librenms—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
librenms/librenms1.46——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 29× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 01:35 UTCEG score recompute
  2. 2026-07-22 22:15 UTCEG score recompute
  3. 2026-07-22 14:05 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
  5. 2026-07-20 17:32 UTCOSV refresh
  6. 2026-07-20 17:04 UTCEPSS rescore
  7. 2026-07-20 17:04 UTCEPSS rescore
  8. 2026-07-19 02:26 UTCEPSS rescore
  9. 2026-07-19 02:26 UTCEPSS rescore
  10. 2026-07-15 16:55 UTCEPSS rescore
  11. 2026-07-15 16:55 UTCEPSS rescore
  12. 2026-07-13 06:10 UTCEPSS rescore
  13. 2026-07-11 08:24 UTCEPSS rescore
  14. 2026-07-09 19:06 UTCEPSS rescore
  15. 2026-07-06 02:20 UTCEPSS rescore
  16. 2026-07-03 12:56 UTCOSV refresh
  17. 2026-07-02 16:54 UTCEPSS rescore
  18. 2026-07-01 15:03 UTCEPSS rescore
  19. 2026-07-01 15:03 UTCEPSS rescore
  20. 2026-06-28 14:04 UTCEPSS rescore
  21. 2026-06-28 04:53 UTCEPSS rescore
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  23. 2026-06-25 13:47 UTCEPSS rescore
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  25. 2026-06-24 14:02 UTCEPSS rescore
Show 42 more
  1. 2026-06-24 14:02 UTCEPSS rescore
  2. 2026-06-23 21:30 UTCEPSS rescore
  3. 2026-06-23 21:30 UTCEPSS rescore
  4. 2026-06-23 21:30 UTCEPSS rescore
  5. 2026-06-21 01:57 UTCEPSS rescore
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  7. 2026-06-18 17:50 UTCEPSS rescore
  8. 2026-06-18 17:50 UTCEPSS rescore
  9. 2026-06-17 17:50 UTCEPSS rescore
  10. 2026-06-17 17:50 UTCEPSS rescore
  11. 2026-06-15 17:45 UTCEPSS rescore
  12. 2026-06-15 02:43 UTCOSV refresh
  13. 2026-06-14 23:15 UTCEPSS rescore
  14. 2026-06-14 23:14 UTCEPSS rescore
  15. 2026-06-12 23:09 UTCEPSS rescore
  16. 2026-06-12 23:09 UTCEPSS rescore
  17. 2026-06-11 13:57 UTCEPSS rescore
  18. 2026-06-10 22:16 UTCEPSS rescore
  19. 2026-06-10 13:19 UTCEPSS rescore
  20. 2026-06-07 15:22 UTCEPSS rescore
  21. 2026-06-07 15:22 UTCEPSS rescore
  22. 2026-06-05 22:45 UTCEPSS rescore
  23. 2026-06-05 22:45 UTCEPSS rescore
  24. 2026-06-05 06:08 UTCEPSS rescore
  25. 2026-06-05 06:08 UTCEPSS rescore
  26. 2026-06-04 13:10 UTCEPSS rescore
  27. 2026-06-02 20:11 UTCEPSS rescore
  28. 2026-06-02 20:11 UTCEPSS rescore
  29. 2026-06-01 13:50 UTCEPSS rescore
  30. 2026-06-01 13:50 UTCEPSS rescore
  31. 2026-05-31 22:29 UTCEPSS rescore
  32. 2026-05-31 00:14 UTCEPSS rescore
  33. 2026-05-31 00:14 UTCEPSS rescore
  34. 2026-05-29 13:41 UTCEPSS rescore
  35. 2026-05-28 13:42 UTCEPSS rescore
  36. 2026-05-28 13:42 UTCEPSS rescore
  37. 2026-05-27 20:10 UTCEG score recompute
  38. 2026-05-27 20:10 UTCGHSA enrichment
  39. 2026-05-27 13:38 UTCEPSS rescore
  40. 2026-05-27 13:38 UTCEPSS rescore
  41. 2026-05-26 07:17 UTCEPSS rescore
  42. 2026-05-26 07:17 UTCEPSS rescore

Publicly available exploits

(4 references)

Working exploit code is in the public domain (1 Metasploit module) (1 GitHub PoC) (2 Exploit-DB entries). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-47044✓ verified
    First seen Jun 28, 2019

    LibreNMS 1.46 - 'addhost' Remote Code Execution

    Open source ↗
  • Exploit-DBEDB-46970✓ verified
    First seen Jun 5, 2019

    LibreNMS - addhost Command Injection (Metasploit)

    Open source ↗
  • GitHub PoCmhaskar/CVE-2018-20434
    First seen Apr 25, 2019

    The official exploit code for LibreNMS v1.46 Remote Code Execution CVE-2018-20434

    Open source ↗
  • Metasploitexploit/linux/http/librenms_addhost_cmd_inject✓ verified
    First seen Dec 16, 2018

    LibreNMS addhost Command Injection

    Open source ↗

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2018-20434?
CVE-2018-20434 is a critical vulnerability published on April 24, 2019. 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 /ajaxoutput.php?id=capture&format=text&type=snmpwalk&hostname=localhost request that triggers…
When was CVE-2018-20434 disclosed?
CVE-2018-20434 was first published in the National Vulnerability Database on April 24, 2019, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-20434 actively exploited?
CVE-2018-20434 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2018-20434?
CVE-2018-20434 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2018-20434?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-20434, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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