Cross-site scripting in LibreNMS - #VU134531
Published: June 15, 2026
Vulnerability identifier: #VU134531
CSH Severity: Medium
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]
CVE-ID: N/A
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary JavaScript in a victim's browser session.
The vulnerability exists due to cross-site scripting in legacy PHP templates under includes/html/ when rendering SNMP-sourced and syslog-sourced data. A remote attacker can supply crafted device metadata or syslog fields to execute arbitrary JavaScript in a victim's browser session.
User interaction is required to view an affected page, and the attacker must control a monitored SNMP device or a syslog source.
Affected software
LibreNMS
Remediation
Install security update from vendor's website.
LibreNMS - update to 26.3.1