LibreNMS before 26.3.1 Stored XSS via SNMP/Syslog Data (CVE-2026-84192) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-84192

LibreNMS before 26.3.1 Stored XSS via SNMP/Syslog Data

Answer in brief

CVE-2026-84192 records a Unknown severity vulnerability in LibreNMS before 26.3.1 Stored XSS via SNMP/Syslog Data. The current sources do not mark it as known exploited. The current feed maps librenms/librenms (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

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

Published Sep 1, 2026Updated Sep 1, 2026Source checked Sep 1, 2026First seen by HOL Sep 1, 2026Material review Sep 1, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. 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 (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
librenms/librenmsgeneric	>=0 <26.3.1	26.3.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for librenms/librenms.
Review the reported fix. Update librenms/librenms to 26.3.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 1, 2026

Sources and claim methodology

Upstream source description

LibreNMS before 26.3.1 contains a stored cross-site scripting vulnerability in legacy PHP templates that output SNMP-sourced and syslog-sourced data without escaping. An attacker who controls a monitored network device can inject arbitrary JavaScript through SNMP interface descriptions or syslog program fields that executes when authenticated users view affected pages.

Quoted source text, attributed separately from HOL analysis.