LibreNMS is a network monitoring system. In versions up to and including 26.4.0, the Proxmox application view is vulnerable to reflected cross-site scripting through the user-supplied instance and vmid GET parameters, which are reflected into the page title without adequate encoding. The parameters are placed into the page title with only strip_tags applied, and the title is then written into an inline document.title assignment through string interpolation, so a single quote terminates the JavaScript string and the remaining input runs as script. An attacker who lures an authenticated user into following a crafted link can execute script in that user's session, enabling actions such as theft of session data. This issue is fixed in version 26.5.0.
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-jmqm-f8q4-v7wx LibreNMS: Reflected XSS via Proxmox instance/vmid GET parameters injected into document.title JavaScript assignment
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 26 Aug 2026 23:45:00 +0000

Type Values Removed Values Added
First Time appeared Librenms
Librenms librenms
Vendors & Products Librenms
Librenms librenms

Wed, 26 Aug 2026 22:00:00 +0000

Type Values Removed Values Added
Description LibreNMS is a network monitoring system. In versions up to and including 26.4.0, the Proxmox application view is vulnerable to reflected cross-site scripting through the user-supplied instance and vmid GET parameters, which are reflected into the page title without adequate encoding. The parameters are placed into the page title with only strip_tags applied, and the title is then written into an inline document.title assignment through string interpolation, so a single quote terminates the JavaScript string and the remaining input runs as script. An attacker who lures an authenticated user into following a crafted link can execute script in that user's session, enabling actions such as theft of session data. This issue is fixed in version 26.5.0.
Title LibreNMS: Reflected XSS in the Proxmox app view via unsanitized instance/vmid parameters
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-26T21:42:01.423Z

Reserved: 2026-05-13T04:38:01.164Z

Link: CVE-2026-45694

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-26T22:16:24.793

Modified: 2026-08-26T22:16:24.793

Link: CVE-2026-45694

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-26T23:30:12Z

Weaknesses