CVE-2026-44900
Deferred Deferred - Pending Action
ECDSA Signature Verification Bypass 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 1.2.1, in SignedPublicKeysTrustValidatorImpl.isTrusted(), the ECDSA signature verification at line 45 discards the boolean return value of Signature.verify(). The method performs certificate chain validation, OCSP check, and signature algorithm setup, but never checks whether the signature actually matches. For any structurally valid signature, it returns true. This vulnerability is fixed in 1.2.1.
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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
CVE-2026-44900
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-295 The product does not validate, or incorrectly validates, a certificate.
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Executive Summary

The vulnerability exists in the epa4all-client Java Client for epa4all / ePA 3.0. Specifically, before version 1.2.1, the method SignedPublicKeysTrustValidatorImpl.isTrusted() incorrectly handles ECDSA signature verification. Although it performs certificate chain validation, OCSP checks, and signature algorithm setup, it ignores the actual result of the signature verification (Signature.verify()). As a result, any structurally valid signature is accepted as trusted, even if it does not match correctly.

Impact Analysis

This vulnerability can lead to a critical security risk because it allows an attacker to bypass proper signature verification. Since any structurally valid signature is accepted, an attacker could potentially present forged or invalid signatures that are treated as trusted. This compromises the integrity and authenticity of communications or data validated by the epa4all-client, potentially leading to unauthorized access or data manipulation.

Mitigation Strategies

To mitigate this vulnerability, upgrade the epa4all-client to version 1.2.1 or later, where the issue with signature verification in SignedPublicKeysTrustValidatorImpl.isTrusted() has been fixed.

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