CVSS 8.1 HIGH
Vulnerability
CVE-2026-44900: epa4all-client has a VAU Signature bypass
Impact 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…
8.1CVSS Score
HIGHSeverity
NOCISA KEV
VulnerabilityImpact Type
📋 Vulnerability Details
| CVE ID | CVE-2026-44900 |
| Vendor | maven |
| Affected Product | com.oviva.telematik:epa4all-client |
| Vulnerability Type | Vulnerability |
| CVSS Score | 8.1 (HIGH) |
| Actively Exploited | ❌ No known exploitation |
| Patch Status | See Vendor Advisory → |
| Reported By | CYBERDUDEBIVASH SENTINEL APEX Intelligence (via github_advisories) |
🔬 Technical Analysis
#
Impact
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.
Patches
Patched in [#34](https://github.com/oviva-ag/epa4all-client/pull/34).
Workarounds
None.
Resources
• [MS-OVIVA-EPA4ALL-d76aec](https://www.machinespirits.com/advisory/d76aec/)
Credits [Machine Spirits](https://machinespirits.com) (contact@machinespirits.de)
• Dr. rer. nat. Simon Weber
• Dipl.-Inf. Volker Schönefeld
• Chiara Fliegner
🎯 Known Indicators of Compromise
{"type":"url","value":"https://github.com/oviva-ag/epa4all-client/pull/34).","confidence_score":0.82,"first_seen":"2026-05-09","source_count":1}
{"type":"url","value":"https://www.machinespirits.com/advisory/d76aec/)","confidence_score":0.82,"first_seen":"2026-05-09","source_count":1}
{"type":"url","value":"https://machinespirits.com)","confidence_score":0.82,"first_seen":"2026-05-09","source_count":1}
{"type":"domain","value":"www.machinespirits.com","confidence_score":0.75,"first_seen":"2026-05-09","source_count":1}
{"type":"domain","value":"machinespirits.com","confidence_score":0.75,"first_seen":"2026-05-09","source_count":1}
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