CVE-2026-45575
Deferred Deferred - Pending Action
Man-in-the-Middle Attack in epa4all-client

Publication date: 2026-05-26

Last updated on: 2026-05-26

Assigner: GitHub, Inc.

Description
epa4all-client is the Java Client for epa4all / ePA 3.0 in the Telematik Infrastruktur. Prior to 1.2.2, an attacker who can MITM the TLS connection between the client and the IDP (within the TI network) can substitute a forged discovery document. The forged document redirects uri_puk_idp_enc and uri_puk_idp_sig to attacker-controlled URLs. The client then encrypts the SMC-B-signed challenge response to the attacker's encryption key and POSTs it to the attacker's auth endpoint. This captures the signed authentication material. This vulnerability is fixed in 1.2.2.
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Meta Information
Published
2026-05-26
Last Modified
2026-05-26
Generated
2026-06-16
AI Q&A
2026-05-27
EPSS Evaluated
2026-06-14
NVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
epa4all epa4all-client 1.2.2
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-347 The product does not verify, or incorrectly verifies, the cryptographic signature for data.
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Executive Summary

The vulnerability exists in the epa4all-client, a Java client used in the Telematik Infrastruktur for ePA 3.0. Before version 1.2.2, an attacker who can perform a man-in-the-middle (MITM) attack on the TLS connection between the client and the Identity Provider (IDP) within the TI network can replace the legitimate discovery document with a forged one.

This forged discovery document redirects certain URIs (uri_puk_idp_enc and uri_puk_idp_sig) to attacker-controlled URLs. As a result, the client encrypts the signed challenge response using the attacker's encryption key and sends it to the attacker's authentication endpoint, allowing the attacker to capture signed authentication material.

This vulnerability was fixed in version 1.2.2 of the epa4all-client.

Impact Analysis

This vulnerability can lead to the compromise of signed authentication material by an attacker who can intercept and manipulate the TLS connection within the TI network.

An attacker could capture sensitive authentication data, potentially allowing unauthorized access or impersonation within the system that uses the epa4all-client.

Because the attacker can obtain signed challenge responses, this could undermine the security and trustworthiness of the authentication process.

Mitigation Strategies

To mitigate this vulnerability, upgrade the epa4all-client to version 1.2.2 or later, as this version contains the fix for the issue.

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