Vulnerability · Published Sep 1, 2026 · Assigned by VulnCheck

CVE-2026-84192LibreNMS before 26.3.1 Stored XSS via SNMP/Syslog Data

High 7.1

In plain English

A high-severity cross-site scripting in librenms from librenms. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.1High

Exploit odds (30 days)0.3%top 73.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

LibreNMS before 26.3.1 contains a stored cross-site scripting vulnerability in legacy PHP templates that output SNMP-sourced and syslog-sourced data without escaping. An attacker who controls a monitored network device can inject arbitrary JavaScript through SNMP interface descriptions or syslog program fields that executes when authenticated users view affected pages.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	librenms/librenms	26.5.0	GHSA-7w8c-qgxg-m7jx

Affected products (as reported)

Vendor	Product	Versions
librenms	librenms	0 – before 26.3.1

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N

References

GitHub Security Advisory (GHSA-7w8c-qgxg-m7jx) vendor-advisory
VulnCheck Advisory: LibreNMS before 26.3.1 Stored XSS via SNMP/Syslog Data third-party-advisory