CVE-2026-52723 (GCVE-0-2026-52723)
Vulnerability from cvelistv5 – Published: 2026-08-18 16:50 – Updated: 2026-08-18 17:38
VLAI
EPSS
VEX
Title
ePA 3.x Integration: VAU Server Authentication Bypass via Circular Certificate Trust
Summary
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 performs VAU server certificate validation in app/vau/VAUProtokoll.py without anchoring the signed_vau_server_pub_keys and AUT_VAU_CertData certificate path to independent trusted material. A network-positioned attacker between the DiGA backend and the ePA system can intercept the VAU handshake, supply attacker-controlled certificate and key material, and satisfy the circular trust relationship. Because TLS certificate verification is also disabled in affected versions, no independent server-authentication layer prevents the attack. The attacker can impersonate the VAU server, control the negotiated session keys, and read or modify all encrypted VAU traffic. This issue is fixed in version 1.3.0.
Severity
9.1 (Critical)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-18 17:38 UTC
CWE
- CWE-295 - Improper Certificate Validation
Assigner
References
5 references
| URL | Tags |
|---|---|
| https://github.com/fbeta-GmbH/ePA3-Service-OpenSo… | x_refsource_CONFIRM |
| https://github.com/fbeta-GmbH/ePA3-Service-OpenSo… | x_refsource_MISC |
| https://github.com/fbeta-GmbH/ePA3-Service-OpenSo… | x_refsource_MISC |
| https://github.com/fbeta-GmbH/ePA3-Service-OpenSo… | x_refsource_MISC |
| https://www.machinespirits.de/advisory/a1da93 | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| fbeta-GmbH | ePA3-Service-OpenSource |
Affected:
< 1.3.0
|
guessed |
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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