WS-2026-0036
Published:August 28, 2026
Updated:August 31, 2026
Multiple legacy PHP template files in LibreNMS output SNMP-sourced and syslog-sourced data into HTML without escaping. The syslog program field is emitted unescaped in includes/html/print-syslog.inc.php while the adjacent msg field is escaped, so an attacker who controls a monitored network device via a compromised SNMP agent or syslog sender can inject arbitrary JavaScript that executes when any authenticated LibreNMS user views the affected pages. Fixed in 26.5.0, which wraps the affected values in the e() escaping helper.
Affected Packages
https://github.com/librenms/librenms.git (GITHUB):
Affected version(s) >=25.1.0 <26.5.0Fix Suggestion:
Update to version 26.5.0librenms/librenms (PHP):
Affected version(s) >=dev-analysis-b0PBV5 <26.5.0Fix Suggestion:
Update to version 26.5.0Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
LOW
Subsequent System Integrity
LOW
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.1
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')