LibreNMS up to 26.1.x HTTP POST Request /port-groups cross site scripting

Summaryinfo

A vulnerability was found in LibreNMS up to 26.1.x. It has been classified as problematic. This issue affects some unknown processing of the file /port-groups of the component HTTP POST Request Handler. This manipulation causes cross site scripting. This vulnerability is registered as CVE-2026-26992. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in LibreNMS up to 26.1.x. It has been declared as problematic. Affected by this vulnerability is an unknown code block of the file /port-groups of the component HTTP POST Request Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. The summary by CVE is:

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

The advisory is shared at github.com. This vulnerability is known as CVE-2026-26992 since 02/17/2026. The exploitation appears to be easy. The attack can be launched remotely. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 26.2.0 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 882fe6f90ea504a3732f83caf89bba7850a5699f is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• LibreNMS

Version

• 26.0
• 26.1

License

• open-source

Website

• Product: https://github.com/librenms/librenms/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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