CVE-2026-62296
HAPI FHIR: XHTML narrative parser unbounded recursion causes StackOverflow denial of service
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 6.9.11, 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.
| CWE | CWE-20 CWE-400 CWE-674 |
| Vendor | hapifhir |
| Product | org.hl7.fhir.core |
| Published | Aug 7, 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
< 6.9.11
hapifhir / ca.uhn.hapi.fhir:org.hl7.fhir.r5
< 6.9.11
hapifhir / ca.uhn.hapi.fhir:org.hl7.fhir.utilities
< 6.9.11
hapifhir / ca.uhn.hapi.fhir:org.hl7.fhir.validation
< 6.9.11
hapifhir / ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli
< 6.9.11