Which products and versions are affected by CVE-2018-20434?

Affected: Librenms versions 1.46; librenms/librenms (composer) versions >= 1.46. The full list is in the CVE brief.

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

It is not listed in any known-exploited vulnerabilities catalog.

Is CVE-2018-20434 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2018-20434?

Public exploit code is available.

Is there a fix for CVE-2018-20434?

No fixed version is listed yet; check the vendor advisory for mitigations.

How urgently should CVE-2018-20434 be patched?

Brandefense priority: patch immediately, because it is very likely to be exploited soon.

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Vulnerability Intelligence

CVE-2018-20434

CriticalPublic exploit

LibreNMS arbitrary OS commands execution

Published May 24, 2022 · Updated Jul 8, 2026 · Also known as GHSA-62q7-qj6g-gvr7

Key Facts

Patch immediately

CVE-2018-20434 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Librenms, librenms/librenms (composer).
It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
EPSS estimates a 71% probability of exploitation in the next 30 days.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

CVSS v3.1

9.8

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

EPSS (30-day exploit likelihood)

71%

Higher than 99.4% of all scored CVEs

Exploited in the wild

No known

Not in a known-exploited catalog

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2018-20434 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

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 Products

2 affected entries in total

Product	Affected versions	Fixed in
LibrenmsLibrenms	1.46	n/a
librenms/librenmscomposer	>= 1.46	n/a

Timeline

Publicly disclosed
May 24, 2022
Last updated
Jul 8, 2026

Weakness Type

CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

References

7 more references in the full CVE brief

FAQ

Common Questions.

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.…
Affected: Librenms versions 1.46; librenms/librenms (composer) versions >= 1.46. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

Is CVE-2018-20434 Running On Your Attack Surface?

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