CVE-2026-56126 pfSense Plus < 26.07 / CE < 2.9.0 Stored XSS via status_monitoring.php
Authenticated users can inject JavaScript into pfSense monitoring pages, executing code in other users' browsers to potentially hijack sessions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-56126?
CVE-2026-56126 is a medium-severity cross-site scripting vulnerability in Netgate pfSense CE, published on 3 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
pfSense Plus before 26.07 and CE before 2.9.0 allow authenticated users with the Status: Monitoring privilege to inject arbitrary JavaScript via graph configuration parameters in /status_monitoring.php. Multiple POST parameters including graph-left, graph-right, time-period, resolution, start-date, end-date, start-time, end-time, graph-type, invert, and refresh-interval are concatenated and written to the global pfSense XML configuration without sanitization, then echoed unsanitized into a JavaScript string context on page render. Because the setting is stored in the global configuration, the payload executes in the browser of every user who visits the Status: Monitoring page.
Weakness: CWE-79
Which versions are affected by CVE-2026-56126?
How do I fix CVE-2026-56126?
No fix has been published for CVE-2026-56126 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-2026-56126 being exploited?
There is no known exploitation of CVE-2026-56126 in the wild and no public exploit code.
Sources
Also known as GHSA-2356-p4rp-xj6q.