CVE-2026-52723Network attack vector

Server impersonation via circular certificate trust

Published Aug 18, 2026 · Updated Aug 18, 2026

Authentication bypass in fbeta GmbH ePA 3.x Integration before 1.3.0 allows attackers to read or modify VAU traffic via MITM. In app/vau/VAUProtokoll.py, the client fetches CertData from the same endpoint it is authenticating and verifies signed_pub_keys against attacker-supplied certificate material instead of an independently pinned TI trust root. Because affected code also requests CertData with TLS verification disabled, a network-positioned attacker between the DiGA backend and the ePA system can impersonate the VAU server, choose session keys, and decrypt or alter encrypted VAU requests and responses.

CVSS severity9.1
Critical
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in fbeta GmbH ePA 3.x Integration before 1.3.0 allows attackers to read or modify VAU traffic via MITM. In app/vau/VAUProtokoll.py, the client fetches CertData from the same endpoint it is authenticating and verifies signed_pub_keys against attacker-supplied certificate material instead of an independently pinned TI trust root. Because affected code also requests CertData with TLS verification disabled, a network-positioned attacker between the DiGA backend and the ePA system can impersonate the VAU server, choose session keys, and decrypt or alter encrypted VAU requests and responses.

The record

CVE
CVE-2026-52723
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
fbeta GmbH
Product
ePA 3.x Integration
Classifications
CWE-295, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

fbeta GmbH · ePA 3.x Integrationversion=< 1.3.0

Published CVSS scores

9.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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