4.3

CVSS Score

3.1

-

CVSS Score

Basic Information

Concerned about an active attack path?

Talk to our security experts and see Miggo in action.

Miggo Vulnerability Database

→

CVE-2026-26989

CVE-2026-26989: LibreNMS has Stored XSS in Alert Rule

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.

(GitHub Advisory)

Miggo Vulnerability Database

→

CVE-2026-26989

CVE-2026-26989:

4.3

CVSS Score

3.1

-

CVSS Score

Basic Information

Is this CVE running in your environment?

Easily map the attack path and prioritize which CVEs are a threat to your organization

Validate Exposure

Technical Details

SSVC / BOD 26-04 ↗

Exploitation NoneAutomatable NoTech Impact Partial

Select your environment

→SSVCDeferfix on upgrade

Runtime reachability resolves your actual outcome.Book a demo

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
librenms/librenms	composer	<= 25.12.0	26.2.0

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The analysis of the provided security advisory and the associated commit 087608cf9f851189847cb8e8e5ad002e59170c58 clearly indicates a stored Cross-Site Scripting (XSS) vulnerability. The vulnerability is located in the includes/html/modal/alert_rule_list.inc.php file. The patch shows that the $rule_display variable, which holds user-controllable content for an alert rule, was previously rendered using only the e() helper for escaping. This was not sufficient to prevent XSS. The fix introduces strip_tags() to sanitize the input by removing HTML tags before it is escaped and displayed. This prevents malicious scripts from being stored and executed in the browsers of users viewing the alert rules page. Since the vulnerable code is not enclosed within a specific function but is part of a PHP include file, the file name itself is the most precise indicator of the vulnerable code location that would be relevant in a runtime analysis.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

Vulnerability Intelligence
Miggo AI

Unlock WAF rules for this CVE

Generate vendor-ready rules for the observed attack patterns, plus reasoning and safe deployment guidance

Get WAF rules

WAF Protection Rules

WAF Rule

W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.

Reasoning

*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.