CVE-2026-33303 OpenEMR Vulnerable to Stored XSS via Unescaped portal_login_username in Credential Print View

Medium 5.4 Published 19 Mar 2026 Updated 24 Mar 2026

Stored XSS in OpenEMR allows patient portal users to execute scripts in clinic staff browsers via unescaped usernames, potentially leading to session hijacking.

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-2026-33303?

CVE-2026-33303 is a medium-severity cross-site scripting vulnerability in Open-Emr Openemr, published on 19 Mar 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

OpenEMR is a free and open source electronic health records and medical practice management application. Versions prior to 8.0.0.2 are vulnerable to stored cross-site scripting (XSS) via unescaped `portal_login_username` in the portal credential print view. A patient portal user can set their login username to an XSS payload, which then executes in a clinic staff member's browser when they open the "Create Portal Login" page for that patient. This crosses from the patient session context into the staff/admin session context. Version 8.0.0.2 fixes the issue.

Weakness: CWE-79

Which versions are affected by CVE-2026-33303?

It affects 1 product.

Products include Open-Emr Openemr.

How do I fix CVE-2026-33303?

No fix has been published for CVE-2026-33303 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-2026-33303 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33303 exists.

All Open-Emr Openemr vulnerabilities

Sources

Also known as GHSA-cp37-pmfx-5mhm.