What’s Vulnerable › Vulnerabilities

CVE-2026-40507: OpenEMR < 8.3.0 Reflected XSS via templateHtml Parameter in Patient Portal

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-19 · updated 2026-10-27
• Weakness: CWE-79

Description

OpenEMR before 8.3.0 contains a reflected cross-site scripting vulnerability in the patient portal template import handler. The templateHtml GET parameter is reflected into the page response without sanitization. An attacker can craft a URL that executes arbitrary JavaScript in the browser of any authenticated user with Forms Administration permissions who visits the link, enabling session hijacking.

Affected products

• openemr: before 8.3.0 — fixed in 8.3.0

How to fix

Upgrade to a fixed version: openemr 8.3.0. Check the vendor advisory for mitigations.

References

• https://github.com/openemr/openemr/commit/ba316dd1d8de1291102da3f20f64240729ff899e
• https://github.com/openemr/openemr/releases/tag/v8_3_0
• https://github.com/openemr/openemr/security/advisories/GHSA-rmmr-8498-463g
• https://www.vulncheck.com/advisories/openemr-reflected-xss-via-templatehtml-parameter-in-patient-portal
• https://github.com/openemr/openemr/security/advisories/GHSA-rmmr-8498-463g

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