CVE-2019-25371 OPNsense 19.1 Reflected XSS via diag_ping.php

Medium 5.1 Published Updated

Unauthenticated attackers can inject malicious scripts via the host parameter in diag_ping.php, leading to arbitrary JavaScript execution in victim browsers.

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-2019-25371?

CVE-2019-25371 is a medium-severity cross-site scripting vulnerability in OPNsense, published on 15 Feb 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

OPNsense 19.1 contains a reflected cross-site scripting vulnerability that allows unauthenticated attackers to inject malicious scripts by exploiting insufficient input validation in the host parameter. Attackers can submit crafted POST requests to the diag_ping.php endpoint with script payloads in the host parameter to execute arbitrary JavaScript in users' browsers.

Weakness: CWE-79

Which versions are affected by CVE-2019-25371?

It affects 1 product.

Products include Opnsense Opnsense.

How do I fix CVE-2019-25371?

No fix has been published for CVE-2019-25371 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-2019-25371 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-25371 exists.

Sources

Also known as GHSA-6rfq-gmm4-49p9.

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