Medium severity · published Aug 19, 2026
CVE-2026-40507
OpenEMR < 8.3.0 Reflected XSS via templateHtml Parameter in Patient Portal
6.1
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 27% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
openemr · openemr
before 8.3.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40507
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-40507
vendor-advisory
https://github.com/openemr/openemr/security/advisories/GHSA-rmmr-8498-463g
release-notes
https://github.com/openemr/openemr/releases/tag/v8_3_0
patch
https://github.com/openemr/openemr/commit/ba316dd1d8de1291102da3f20f64240729ff899e
third-party-advisory
https://www.vulncheck.com/advisories/openemr-reflected-xss-via-templatehtml-parameter-in-patient-portal
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