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Fencer Vulns
high 8.1

CVE-2026-84189 json

LibreNMS before 26.7.0 Stored XSS via Oxidized API

published 2026-08-18 2 mo ago modified 2026-10-08 31 d ago also GHSA-7gww-x7fh-jf9j , EUVD-2026-69026

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

LibreNMS through 26.4.0 renders JSON fields (name, ip, model, author, commit message) returned by the admin-configurable Oxidized integration URL (oxidized.url) into the device showconfig page without applying htmlspecialchars(). An administrator who points the Oxidized URL at an attacker-controlled server (SSRF) can cause it to return malicious JSON, resulting in stored/persistent cross-site scripting affecting all users who view any device's showconfig tab. Fixed in 26.7.0.

Patch / fix

  • packagist librenms/librenms 26.7.0
  • librenms librenms 26.7.0

CISA SSVC

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

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/librenms/librenms/security/advisories/GHSA-7gww-x7fh-jf9j referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
CNA 4.0 9.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/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
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
packagist librenms/librenms
<26.7.0
26.7.0

Affected products

  • librenms librenms

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-918 Server-Side Request Forgery

References

Sources

Fencer Vulns 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.