CVE-2026-26989 LibreNMS has Stored XSS in Alert Rule
Administrators can inject malicious scripts into Alert Rules, leading to code execution in other users' browsers.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-26989?
CVE-2026-26989 is a medium-severity cross-site scripting vulnerability in Librenms Librenms, published on 20 Feb 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. Versions 25.12.0 and below are affected by a Stored Cross-Site Scripting (XSS) vulnerability in the Alert Rules workflow. An attacker with administrative privileges can inject malicious scripts that execute in the browser context of any user who accesses the Alert Rules page. This issue has been fixed in version 26.2.0.
Weakness: CWE-79
Which versions are affected by CVE-2026-26989?
2 open source packages ship an affected version, including librenms/librenms. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
librenms/librenms Packagist | All versions | 26.2.0 |
librenms/librenms Packagist | All versions | 26.2.0 |
Products include Librenms Librenms.
How do I fix CVE-2026-26989?
Upgrade librenms/librenms to 26.2.0 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-26989 being exploited?
There is no known exploitation of CVE-2026-26989 in the wild and no public exploit code.
Other vulnerabilities in Librenms Librenms
Sources
Also known as GHSA-6xmx-xr9p-58p7.