CVE-2026-44900 HIGH

CVE-2026-44900: epa4all-client: VAU Signature bypass

Vendor Oviva-Ag
Product epa4all-client
Weakness CWE-295
Published May 26, 2026
Last update May 28, 2026

CVSS base score

8.1/10
Attack vector Adjacent
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

May 26, 2026 CVE published
May 28, 2026 Record updated