CVE-2026-55470: CWE-1333: Inefficient Regular Expression Complexity in hapifhir org.hl7.fhir.core
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.
AI Analysis
Technical Summary
The vulnerability in HAPI FHIR's org.hl7.fhir.core component involves inefficient regular expression complexity (CWE-1333) in the DSTU2 module. Specifically, before version 6.9.10, the FHIRPathEngine.matches() method invokes raw String.matches() without applying regex timeout protections, unlike the replaceMatches() method which was updated. This allows an unauthenticated attacker to trigger catastrophic regex backtracking, leading to denial of service by exhausting server CPU. The issue is fixed in version 6.9.10.
Potential Impact
An unauthenticated attacker can exploit this vulnerability to cause denial of service by triggering catastrophic regex backtracking, resulting in high CPU usage and potential server resource exhaustion. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Upgrade to HAPI FHIR version 6.9.10 or later, where this vulnerability is fixed. Patch status is confirmed by the vendor advisory indicating the issue is resolved in 6.9.10. No other mitigations are specified.
CVE-2026-55470: CWE-1333: Inefficient Regular Expression Complexity in hapifhir org.hl7.fhir.core
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.
CVSS v3.1
Score 7.5high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in HAPI FHIR's org.hl7.fhir.core component involves inefficient regular expression complexity (CWE-1333) in the DSTU2 module. Specifically, before version 6.9.10, the FHIRPathEngine.matches() method invokes raw String.matches() without applying regex timeout protections, unlike the replaceMatches() method which was updated. This allows an unauthenticated attacker to trigger catastrophic regex backtracking, leading to denial of service by exhausting server CPU. The issue is fixed in version 6.9.10.
Potential Impact
An unauthenticated attacker can exploit this vulnerability to cause denial of service by triggering catastrophic regex backtracking, resulting in high CPU usage and potential server resource exhaustion. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Upgrade to HAPI FHIR version 6.9.10 or later, where this vulnerability is fixed. Patch status is confirmed by the vendor advisory indicating the issue is resolved in 6.9.10. No other mitigations are specified.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-16T22:10:37.608Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4ec4a5c9d9e3dbe3c8d489
Added to database: 07/08/2026, 21:44:05 UTC
Last enriched: 07/16/2026, 10:19:23 UTC
Last updated: 08/22/2026, 10:52:10 UTC
Views: 99
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