What’s Vulnerable › Vulnerabilities

CVE-2026-26991: LibreNMS vulnerable to Stored Cross-site Scripting through unsanitized /device-groups name

• Severity: medium (CVSS 4.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-02-20 · updated 2026-06-17
• Weakness: CWE-79

Description

LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. In versions 26.1.1 and below, the device group name is not sanitized, allowing attackers with admin privileges to perform Stored Cross-Site Scripting (XSS) attacks. When a user adds a device group, an HTTP POST request is sent to the Request-URI "/device-groups". The name of the newly created device group is stored in the value of the name parameter. After the device group is created, the entry is displayed along with relevant buttons such as Rediscover Devices, Edit, and Delete. This issue has been fixed in version 26.2.0.

Affected products

• librenms: before 26.2.0 — fixed in 26.2.0

How to fix

Upgrade to a fixed version: librenms 26.2.0. Check the vendor advisory for mitigations.

References

• https://github.com/librenms/librenms/commit/64b31da444369213eb4559ec1c304ebfaa0ba12c
• https://github.com/librenms/librenms/pull/19041
• https://github.com/librenms/librenms/releases/tag/26.2.0
• https://github.com/librenms/librenms/security/advisories/GHSA-5pqf-54qp-32wx

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