What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-26 · updated 2026-07-24
• Weakness: CWE-295

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.

Affected products

• com.oviva.telematik epa4all-client: before 1.2.1
• oviva-ag epa4all-client: before 1.2.1

References

• https://github.com/oviva-ag/epa4all-client/pull/34
• https://github.com/oviva-ag/epa4all-client/security/advisories/GHSA-g8r3-5hwf-qp96

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