Authorization bypass through user-controlled key in OpenEMR - CVE-2026-33934
Published: April 23, 2026
Vulnerability identifier: #VU127361
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-33934
CWE-ID: CWE-639
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: OpenEMR
Affected software:
OpenEMR
OpenEMR
Detailed vulnerability description
The vulnerability allows a remote user to disclose sensitive information.
The vulnerability exists due to authorization bypass through a user-controlled key in portal/sign/lib/show-signature.php when handling portal requests with attacker-controlled user and type values. A remote user can send a specially crafted POST request to disclose sensitive information.
Only deployments with the patient portal enabled are vulnerable. When mode is set to fetch_info, the endpoint also returns the targeted staff member's full name.
How to mitigate CVE-2026-33934
Install security update from vendor's website.