ECDSA Signature Validation Flaw in epa4all-client for Java by oviva AG
CVE-2026-44900

8.1HIGH

Key Information:

Vendor

Oviva-ag

Status
Epa4all-client
Vendor
CVE Published:
26 May 2026

What is CVE-2026-44900?

The epa4all-client, a Java client for epa4all / ePA 3.0 within the Telematik Infrastruktur, contains a significant flaw in its ECDSA signature verification process. In versions prior to 1.2.1, the implementation in SignedPublicKeysTrustValidatorImpl.isTrusted() incorrectly discards the return value of the Signature.verify() method. This oversight leads to a scenario where the method always returns true for any structurally valid signature, regardless of whether it actually matches the data, thereby undermining the integrity checks intended for certificate chain validation and OCSP status checks. It is crucial for users to upgrade to version 1.2.1 or later to mitigate this vulnerability.

Affected Version(s)

epa4all-client < 1.2.1

epa4all-client < 1.2.1

References

https://github.com/oviva-ag/epa4all-client/security/advis...
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https://github.com/oviva-ag/epa4all-client/pull/34
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CVSS V3.1

Score:
8.1
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Adjacent Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.