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Fencer Intel
medium 5.8

CVE-2026-84193 json

LibreNMS through 26.2.0 Stored Cross-Site Scripting via SNMP

published 3mo ago modified 2mo ago also EUVD-2026-69030 , GHSA-v5jp-f342-234h

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository librenms/librenms. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
5.8
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 28%
public exploits
0
none known

Summary

LibreNMS through 26.2.0 contains a stored cross-site scripting vulnerability in legacy PHP template pages that render unescaped SNMP-sourced data fields including BGP peer descriptions, VRF names, process information, and SLA tags. Attackers with device management access or network access to enroll a rogue SNMP device can inject malicious JavaScript that executes when admins view affected routing and device pages, enabling credential theft and CSRF token exfiltration.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/librenms/librenms/security/advisories/GHSA-v5jp-f342-234h referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.8 CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 5.8 CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • librenms librenms

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of librenms/librenms published their own advisory on GitHub. Reviewed sources take precedence over it.