CVE-2026-55470

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

HIGH
7.5
CVSS Score
Published: July 8, 2026 at 09:27 PM UTC
Updated: October 25, 2026 at 05:10 PM UTC
1 product affected across 1 vendorHL7 Fhir Core

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Severity
HIGH7.5
Exploit prediction
EPSS 0.7%
SSVC
PoC

Description

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.9.10
Affected range stops below 6.9.10, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-1333

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