CVE-2026-55470

HIGH 7.5

HAPI FHIR: DSTU2 FHIRPathEngine.matches() missing RegexTimeout protection allows ReDoS

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-1333
Vendor	hapifhir
Product	org.hl7.fhir.core
Published	Jul 8, 2026
Last Updated	Jul 9, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

hapifhir / org.hl7.fhir.core

< 6.9.10

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-fxj4-p9xp-37v5 github.com: https://github.com/hapifhir/org.hl7.fhir.core/commit/56376f7986222626af061ca7fc27ee1ab030e590 github.com: https://github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.10