CVE-2026-84191 LibreNMS before 26.5.0 Stored XSS via SNMP VRF fields
Attackers controlling monitored devices can inject JavaScript via SNMP fields, executing code in administrators' browsers viewing VRF pages.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-84191?
CVE-2026-84191 is a medium-severity cross-site scripting vulnerability in librenms, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
LibreNMS before 26.5.0 contains stored cross-site scripting vulnerabilities in VRF display pages where mplsVpnVrfDescription, vrf_name, and mplsVpnVrfRouteDistinguisher fields from SNMP polling are rendered without sanitization. Attackers controlling a monitored network device can inject arbitrary JavaScript through SNMP responses that executes in the browser of any user viewing VRF-related pages.
Weakness: CWE-79
Which versions are affected by CVE-2026-84191?
How do I fix CVE-2026-84191?
No fix has been published for CVE-2026-84191 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-84191 being exploited?
There is no known exploitation of CVE-2026-84191 in the wild and no public exploit code.
Sources
Also known as GHSA-3cvh-rhc6-7rhc, GHSA-g993-wffj-m3gv.