GHSA-fqx6-693c-f55g: librenms/librenms (CVE-2026-27016)

Package	Ecosystem	Affected	Fixed in
librenms/librenms	Packagist	>=24.10.0, <26.2.0	26.2.0

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

LibreNMS versions from 24.10.0 before 26.2.0 are affected by a stored cross-site scripting flaw in the Custom OID feature, where the unit field is saved without sanitization and rendered without HTML escaping. An attacker needs an account with device edit permissions to store a malicious unit value, which then runs in the browsers of users who view device graphs, potentially enabling session cookie theft or actions taken as other users. Upgrade to LibreNMS 26.2.0 or later.

Written 3 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
5.4	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0026, the 18th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:26 UTC First seen by agentprime
31 Oct 2026, 14:26 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.