CVE-2026-84193Public exploitNetwork attack vectorHinoki check available

Credential theft via unescaped SNMP template fields

Published Sep 1, 2026 · Updated Sep 2, 2026

Stored XSS in LibreNMS 26.2.0 and earlier allows remote attackers to run JavaScript in administrators' browsers via crafted SNMP data. Legacy PHP templates directly echo database fields populated by SNMP polling, including BGP descriptions, VRF values, process data, and SLA tags, without HTML escaping. Exploitation requires device management access or a rogue enrolled SNMP device and an administrator to view an affected page, exposing SNMP credentials and CSRF tokens.

CVSS severity5.8
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in LibreNMS 26.2.0 and earlier allows remote attackers to run JavaScript in administrators' browsers via crafted SNMP data. Legacy PHP templates directly echo database fields populated by SNMP polling, including BGP descriptions, VRF values, process data, and SLA tags, without HTML escaping. Exploitation requires device management access or a rogue enrolled SNMP device and an administrator to view an affected page, exposing SNMP credentials and CSRF tokens.

The record

CVE
CVE-2026-84193
Published
Sep 1, 2026
Updated
Sep 2, 2026
Vendor
LibreNMS
Product
LibreNMS
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

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

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=0 <=26.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

LibreNMS · LibreNMSversion=0 <=26.2.0

Published CVSS scores

5.8VulnCheckCVSS:4.0/AV:N/AC:H/AT:N/PR:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

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

Technologies

Your stack

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Your stack

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