CVE-2026-103939 in OpenEMR
Summary
by MITRE • 11/05/2026
OpenEMR is a free and open source electronic health records and medical practice management application. Prior to 8.3.0, interface/modules/custom_modules/oe-module-weno/scripts/file_download.php has no ACL or CSRF check and ignores the result of validateAdminCredentials(). When the Weno module is enabled, the default GET path calls PharmacyService::removeWenoPharmacies() before attempting a refetch, allowing any authenticated user to truncate the weno_pharmacy table and allowing a cross-site request to trigger the same operation through a logged-in victim. A failed later download can leave the e-prescribing pharmacy directory empty and unavailable. This issue is fixed in version 8.3.0.
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Analysis
by VulDB Data Team • 11/05/2026
OpenEMR serves as a widely deployed open-source electronic health records system, managing sensitive patient data and clinical workflows for medical practices. Within this ecosystem, custom modules extend core functionality to address specific operational needs, such as the Weno module which facilitates e-prescribing services by maintaining a directory of pharmacies. A critical security flaw was identified in versions prior to 8.3.0 within the file_download.php script located at interface/modules/custom_modules/oe-module-weno/scripts/. This component is responsible for handling requests related to pharmacy data management, specifically interacting with the PharmacyService class to manage entries in the weno_pharmacy database table. The vulnerability stems from a fundamental failure in access control and request validation mechanisms within this specific endpoint.
The technical root cause of this vulnerability lies in the absence of Access Control List checks and Cross-Site Request Forgery protections on the GET path for file_download.php. More critically, the script invokes the validateAdminCredentials() function but completely ignores its return value. This design flaw means that even if a user lacks administrative privileges or fails authentication validation, the subsequent logic proceeds to execute sensitive operations regardless of the outcome. Specifically, when the Weno module is enabled, the code path triggers PharmacyService::removeWenoPharmacies(), which deletes all entries from the weno_pharmacy table. This operation occurs before any potential refetching logic can restore or validate data integrity, leading to immediate and irreversible truncation of the pharmacy directory for e-prescribing services.
From an operational perspective, this vulnerability allows any authenticated user with access to OpenEMR to disrupt critical clinical workflows by emptying the list of available pharmacies. This denial of service effect prevents healthcare providers from sending electronic prescriptions, potentially delaying patient care and creating significant administrative overhead as staff must manually re-populate or restore the pharmacy directory. Furthermore, because there are no CSRF tokens implemented in this endpoint, an attacker can craft a malicious web page that forces a logged-in administrator or authorized user to trigger this deletion request without their knowledge or consent. This combination of broken access control and lack of anti-CSRF measures significantly lowers the barrier for exploitation, allowing non-privileged users to cause substantial disruption through simple social engineering tactics such as phishing links.
This vulnerability aligns with CWE-862, which describes Missing Authorization, as the application fails to enforce proper restrictions on authenticated users regarding sensitive actions. Additionally, it corresponds to CWE-352, Cross-Site Request Forgery (CSRF), due to the absence of anti-CSRF tokens that would prevent state-changing requests from being initiated by third-party sites. In terms of adversary tactics, this flaw facilitates ATT&CK technique T1498, Network Denial of Service, specifically through resource exhaustion or service disruption via application logic abuse rather than network-level flooding. The impact is severe because it compromises the availability component of the CIA triad for a core clinical function, directly affecting patient care continuity.
To mitigate this vulnerability, organizations running OpenEMR must upgrade to version 8.3.0 or later, where these access control and CSRF protections have been implemented. For environments that cannot immediately patch due to compatibility constraints, temporary mitigations include restricting web server access to the interface/modules/custom_modules/oe-module-weno/scripts/ directory to only trusted internal IP addresses if possible, although this is not a complete solution given the authenticated nature of the attack. It is also advisable to review audit logs for unusual patterns in pharmacy record deletions and ensure that database backups are frequent enough to allow rapid restoration of the weno_pharmacy table in the event of an incident. Long-term remediation should involve enforcing strict input validation, implementing robust CSRF token verification on all state-changing endpoints, and ensuring that administrative credential checks actually gatekeep access to sensitive functions rather than being ignored as dead code.