CVE-2026-49485: Hapifhir org.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 6.9.9 and 6.9.4.2, all implementations of FHIRPathEngine accept arbitrary FHIRPath expressions and evaluate them without input validation, and the FHIRPath functions matches(), matchesFull(), and replaceMatches() pass user-controlled regular expressions to Java's Pattern.compile() and String.replaceAll() through an incomplete timeout utility. An attacker can send a resource containing an evil regex pattern that causes catastrophic backtracking, exhausting CPU resources and causing denial of service in the FHIR Validator HTTP endpoint and affected org.hl7.fhir.* modules. This issue is fixed in versions 6.9.9 and 6.9.4.2.

Affected products

• Hapifhir org.hl7.fhir.core: before 6.9.4.2 (fixed in 6.9.4.2); from 6.9.5, before 6.9.9 (fixed in 6.9.9)

Published 2026-07-17. Last modified 2026-07-23.