LibreNMS: Reflected XSS in the Proxmox app view via unsanitized instance/vmid parameters (CVE-2026-45694) | HOL Guard CVE

Medium · CVSS 5.4CVE-2026-45694GHSA-JMQM-F8Q4-V7WX

LibreNMS: Reflected XSS in the Proxmox app view via unsanitized instance/vmid parameters

Answer in brief

CVE-2026-45694 records a Medium severity (CVSS 5.4) vulnerability in LibreNMS: Reflected XSS in the Proxmox app view via unsanitized instance/vmid parameters. The current sources do not mark it as known exploited. The current feed maps librenms/librenms (composer), librenms/librenms (generic), librenms/librenms (packagist). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 26, 2026Updated Aug 26, 2026Source checked Aug 26, 2026First seen by HOL Aug 12, 2026Material review Aug 26, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.4
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 5.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps librenms/librenms (composer), librenms/librenms (generic), librenms/librenms (packagist). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
librenms/librenmscomposer	<=26.4.0	26.5.0
librenms/librenmsgeneric	< 26.5.0	Not reported
librenms/librenmspackagist	>=0 <26.5.0	26.5.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for librenms/librenms, librenms/librenms, librenms/librenms.
Review the reported fix. Update librenms/librenms to 26.5.0; librenms/librenms to 26.5.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 12, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.