CVE-2026-55470: Hapifhir HL7 Fhir Core

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.10, the fix for CVE-2026-45367 incompletely patched the DSTU2 module, leaving FHIRPathEngine.matches() in org.hl7.fhir.dstu2/utils/FHIRPathEngine.java to call raw String.matches(sw) without RegexTimeout protection while replaceMatches() was updated, allowing an unauthenticated attacker to trigger catastrophic regex backtracking and exhaust server CPU. This issue is fixed in version 6.9.10.

Affected products

• Hapifhir HL7 Fhir Core: before 6.9.10 (fixed in 6.9.10)

Published 2026-07-08. Last modified 2026-07-16.