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CVE-2026-62296

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

Published: Aug 7, 2026Updated: Aug 10, 2026 Sources: CVE List NVDCWE-20
7.5HIGH
NVD MITRE
EPSS Score
0.3%
Top 80.0%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-20CWE-400CWE-674

Affected Products

hapifhir
oss-projectaka org.hl7.fhir.core, hl7 fhir core
org.hl7.fhir.coreOn-prem
OSS Libraries / generic-library
ca.uhn.hapi.fhir:org.hl7.fhir.r5On-prem
OSS Libraries / generic-library
ca.uhn.hapi.fhir:org.hl7.fhir.utilitiesOn-prem
OSS Libraries / generic-library
ca.uhn.hapi.fhir:org.hl7.fhir.validationOn-prem
OSS Libraries / generic-library
ca.uhn.hapi.fhir:org.hl7.fhir.validation.cliOn-prem
OSS Libraries / generic-library

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Impact
Initial Access
View detailed technique mapping

References

https://github.com/hapifhir/org.hl7.fhir.core/commit/396f447500407693d6ae1e64db59782862ca7506
github.com
https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-5v24-q6x8-hc38
github.com

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