HAPI FHIR: XHTML narrative parser unbounded recursion causes StackOverflow denial of service

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-62296
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-07 20:16:52 UTC
Updated2026-08-10 14:17:25 UTC
DescriptionHAPI 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

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

EPSS: 0.002780000 probability, percentile 0.200190000 (date 2026-08-10)

Problem Types: CWE-20 | CWE-400 | CWE-674 | CWE-20 CWE-20: Improper Input Validation | CWE-400 CWE-400: Uncontrolled Resource Consumption | CWE-674 CWE-674: Uncontrolled Recursion

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Hapifhir Org.hl7.fhir.core affected < 6.9.11 Not specified
CNA Hapifhir Ca.uhn.hapi.fhirorg.hl7.fhir.r5 affected < 6.9.11 Not specified
CNA Hapifhir Ca.uhn.hapi.fhirorg.hl7.fhir.utilities affected < 6.9.11 Not specified
CNA Hapifhir Ca.uhn.hapi.fhirorg.hl7.fhir.validation affected < 6.9.11 Not specified
CNA Hapifhir Ca.uhn.hapi.fhirorg.hl7.fhir.validation.cli affected < 6.9.11 Not specified

References

ReferenceSourceLinkTags
github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-5v24-q6x8... 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/hapifhir/org.hl7.fhir.core/commit/396f447500407693d6ae1e64db5... [email protected] github.com
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