CVE-2026-50578 in Epa3-Service-Opensource
Summary
by MITRE • 08/18/2026
ePA 3.x Integration implements the authorization workflow and writes Medical Information Objects to Germany's electronic patient record. Prior to 1.3.0, ePA 3.x Integration disables TLS certificate verification for both ePA connections in app/vau/VAUProtokoll.py and Konnektor connections in app/konnektor/Konnektor.py. A network-positioned attacker can present an arbitrary certificate, terminate the TLS connection, and intercept ePA traffic. The VAU protocol does not provide an effective fallback because its application-layer certificate validation is also broken in affected versions. The Konnektor session uses self.session.verify set to False while the client authenticates with self.session.cert, so an attacker impersonating the Konnektor can receive the client's mutual TLS certificate exchange and observe smartcard operations. This issue is fixed in version 1.3.0.
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Analysis
by VulDB Data Team • 08/18/2026
The ePA 3.x Integration software serves as a critical component for implementing authorization workflows and writing Medical Information Objects to Germany’s electronic patient record system, known as the elektronische Patientenakte or ePA. In versions prior to 1.3.0, this application contains severe cryptographic implementation flaws that fundamentally compromise the security of data transmission between the client application and backend services. The vulnerability stems from a deliberate disabling of Transport Layer Security certificate verification in two distinct connection modules: VAUProtokoll.py for electronic patient record connections and Konnektor.py for konnektor connections. This configuration error effectively strips away the primary defense mechanism against man-in-the-middle attacks, allowing any network-positioned attacker to intercept sensitive health data without detection.
In the context of ePA connections handled by VAUProtokoll.py, the application disables TLS certificate verification entirely. This allows an adversary positioned on the network path to present a self-signed or arbitrary certificate during the handshake process. Because the client does not validate that this certificate is signed by a trusted Certificate Authority and matches the expected hostname, it accepts the connection as legitimate. Consequently, the attacker can terminate the encrypted session and establish their own malicious TLS tunnel between the victim application and the actual server. This enables the interception of all transmitted medical information objects and authorization tokens. The VAU protocol itself does not provide an effective fallback mechanism because its application-layer certificate validation is also broken in these affected versions, meaning there is no secondary check to catch this deception at a higher level of the stack.
The vulnerability extends to Konnektor connections managed by Konnektor.py, where the security posture is equally compromised but through a different configuration pattern. The session object explicitly sets self.session.verify to False, which disables server certificate validation for outgoing requests. While the client does authenticate itself using mutual TLS via self.session.cert, this one-way authentication provides insufficient protection against impersonation of the remote service. An attacker can act as a rogue Konnektor and present an invalid or forged certificate during the initial handshake. Since verification is disabled, the client proceeds with the connection. This allows the malicious actor to participate in the mutual TLS exchange, thereby obtaining the client’s private key material indirectly through observation of smartcard operations or by capturing session tokens exchanged over the now-unencrypted logical channel relative to server identity. The attacker can thus impersonate the Konnektor and observe sensitive authentication flows that should remain confidential.
From a classification perspective, this vulnerability aligns with CWE-295 Improper Certificate Validation, as the software fails to properly validate X.509 certificates presented by remote parties during TLS handshakes. It also maps directly to MITRE ATT&CK technique T1078 Valid Accounts and potentially T1041 Exfiltration Over C2 Channel if used for data theft, though more accurately it represents a failure in authentication integrity that facilitates interception consistent with CWE-319 Cleartext Transmission of Sensitive Information. The operational impact is severe given the sensitivity of health data protected under regulations such as GDPR and specific German healthcare security standards like BSI IT-Grundschutz. Interception of ePA traffic could lead to unauthorized access to patient histories, prescription records, and diagnostic results, resulting in significant privacy violations and potential misuse of personal health information for fraud or blackmail.
Mitigation requires immediate upgrading to version 1.3.0 or later where these certificate verification checks are correctly re-enabled. Until an upgrade is possible, organizations should consider network-level controls such as strict firewall rules that restrict ePA client traffic only to known, verified IP addresses of authorized konnektors and ePA servers. Additionally, implementing TLS inspection proxies with proper CA trust stores can help detect anomalies if the vulnerable software must remain in use temporarily. However, relying on perimeter defenses is not a substitute for fixing the application code, as internal network compromises or compromised routers could still bypass these controls. The root cause lies in insecure coding practices where security configurations are disabled during development or deployment without adequate review, highlighting the need for rigorous static and dynamic analysis of cryptographic implementations in healthcare software.