CVE-2026-84192Public exploitNetwork attack vectorHinoki check available

Stored XSS via unescaped SNMP and syslog fields

Published Sep 1, 2026 · Updated Sep 1, 2026

Stored XSS in legacy PHP templates in LibreNMS before 26.3.1 allows remote attackers to execute JavaScript through SNMP or syslog data. Templates including print-syslog.inc.php and functions.inc.php concatenate the syslog program field and SNMP ifAlias values into HTML without encoding. Exploitation requires control of a monitored SNMP device or syslog sender and an authenticated user's visit, exposing that browser session to script-driven data access and actions.

CVSS severity7.1
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stored XSS in legacy PHP templates in LibreNMS before 26.3.1 allows remote attackers to execute JavaScript through SNMP or syslog data. Templates including print-syslog.inc.php and functions.inc.php concatenate the syslog program field and SNMP ifAlias values into HTML without encoding. Exploitation requires control of a monitored SNMP device or syslog sender and an authenticated user's visit, exposing that browser session to script-driven data access and actions.

The record

CVE
CVE-2026-84192
Published
Sep 1, 2026
Updated
Sep 1, 2026
Vendor
LibreNMS
Product
LibreNMS
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <26.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LibreNMS · LibreNMSversion=0 <26.3.1

Published CVSS scores

7.1VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
7.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo