Librenms
CVE-2026-26991
MEDIUM
GHSA-5pqf-54qp-32wx
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS 4.8 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: High. User interaction: Required. Exploitation requires authentication. Exploitable via remote/network. Public exploit/POC available. |
| Exploit ScenarioDerived | A remote attacker (requires authentication) could exploit this vulnerability to compromise the affected system. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Stored XSS in LibreNMS versions 26.1.1 and below allows authenticated administrators to inject malicious scripts through unsanitized device group names, which execute when other users view the group management interface. Public exploit code exists for this vulnerability, affecting LibreNMS deployments across multiple supported platforms. The vulnerability has been patched in version 26.2.0.
Earlier versions of this analysis (1)
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. [CVSS 4.8 MEDIUM]
RemediationAI
A vendor patch is available — apply it immediately. Fixed in version 26.2.0.. Implement output encoding and Content Security Policy headers. Restrict network access to the affected service where possible.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in composer
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Classified as CWE-79 (Cross-site Scripting (XSS)). Affects the value of the name component of Librenms. 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
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
Lifecycle Timeline
3DescriptionGitHub Advisory
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.
Executive ViewAI
Organizations using LibreNMS should be aware of moderate risk from CVE-2026-26991, a cross-site scripting vulnerability rated CVSS 4.8. Attackers could inject scripts to steal sessions or perform actions as authenticated users. Proof-of-concept code is publicly available. A patch is available and should be applied during regular vulnerability management.
Apply vendor patch. If patching is delayed: implement CSP headers, enable HttpOnly cookies, deploy WAF XSS rules.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.
Affected Products (CPE)GitHub Advisory
An issue was discovered in LibreNMS through 1.47. Rated high severity (CVSS 7.2), this vulnerability is remotely exploit
Librenms 21.11.0 is affected by a path manipulation vulnerability in includes/html/pages/device/showconfig.inc.php. Rate
An issue was discovered in LibreNMS through 1.47. Rated critical severity (CVSS 9.8), this vulnerability is remotely exp
Authentication bypass in the LibreNMS REST API (all versions before 26.8.0) lets unauthenticated remote attackers reach
SQL injection in LibreNMS 25.12.0 and below. PoC and patch available.
An issue was discovered in LibreNMS through 1.47. Rated critical severity (CVSS 9.1), this vulnerability is remotely exp
SQL injection in LibreNMS versions 25.12.0 and below allows authenticated users to extract sensitive database informatio
LibreNMS is an open-source, PHP/MySQL/SNMP-based network monitoring system. Rated high severity (CVSS 8.8), this vulnera
An issue was discovered in LibreNMS before 1.65.1. Rated high severity (CVSS 8.8), this vulnerability is remotely exploi
An issue was discovered in LibreNMS 1.50.1. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable,
An issue was discovered in LibreNMS through 1.47. Rated high severity (CVSS 8.8), this vulnerability is remotely exploit
Command injection in LibreNMS's Virtualization Discovery module enables authenticated administrator-level users to execu
Exploit-DB