CVE-2026-62296: CWE-20: Improper Input Validation in hapifhir org.hl7.fhir.core
HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.11, XhtmlParser.java imposes no maximum element nesting depth, so a deeply nested text.div narrative triggers unbounded recursion between parseElementInner() and parseElement(), raising a StackOverflowError. An attacker who can submit FHIR resources containing such narratives can thus crash a parsing or validation worker thread, affecting validator services and any application that parses attacker-supplied FHIR JSON or XML. This issue is fixed in version 6.9.11.
AI Analysis
Technical Summary
The vulnerability in HAPI FHIR's org.hl7.fhir.core component arises from the XhtmlParser.java class lacking a maximum element nesting depth check. This permits an attacker to craft FHIR resources with deeply nested text.div narratives that cause unbounded recursion between parseElementInner() and parseElement() methods, resulting in a StackOverflowError. This denial-of-service condition affects any service or application that parses or validates such maliciously crafted FHIR resources. The vulnerability is addressed in version 6.9.11.
Potential Impact
Exploitation of this vulnerability leads to denial of service by crashing parsing or validation worker threads via StackOverflowError. This disrupts validator services and any application that processes attacker-supplied FHIR JSON or XML containing deeply nested narratives. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Upgrade to HAPI FHIR version 6.9.11 or later, where this issue is fixed. No other mitigations are indicated by the vendor advisory.
CVE-2026-62296: CWE-20: Improper Input Validation 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 6.9.11, XhtmlParser.java imposes no maximum element nesting depth, so a deeply nested text.div narrative triggers unbounded recursion between parseElementInner() and parseElement(), raising a StackOverflowError. An attacker who can submit FHIR resources containing such narratives can thus crash a parsing or validation worker thread, affecting validator services and any application that parses attacker-supplied FHIR JSON or XML. This issue is fixed in version 6.9.11.
CVSS v3.1
Score 7.5high
Affected software
hapifhir
org.hl7.fhir.core
hapifhir
ca.uhn.hapi.fhir:org.hl7.fhir.r5
hapifhir
ca.uhn.hapi.fhir:org.hl7.fhir.utilities
hapifhir
ca.uhn.hapi.fhir:org.hl7.fhir.validation
hapifhir
ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in HAPI FHIR's org.hl7.fhir.core component arises from the XhtmlParser.java class lacking a maximum element nesting depth check. This permits an attacker to craft FHIR resources with deeply nested text.div narratives that cause unbounded recursion between parseElementInner() and parseElement() methods, resulting in a StackOverflowError. This denial-of-service condition affects any service or application that parses or validates such maliciously crafted FHIR resources. The vulnerability is addressed in version 6.9.11.
Potential Impact
Exploitation of this vulnerability leads to denial of service by crashing parsing or validation worker threads via StackOverflowError. This disrupts validator services and any application that processes attacker-supplied FHIR JSON or XML containing deeply nested narratives. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Upgrade to HAPI FHIR version 6.9.11 or later, where this issue is fixed. No other mitigations are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-13T18:37:08.488Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a772657bf8831d539846b9a
Added to database: 08/08/2026, 12:51:35 UTC
Last enriched: 08/15/2026, 15:33:55 UTC
Last updated: 09/22/2026, 01:52:44 UTC
Views: 75
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