CVE-2026-62296: HAPI FHIR: XHTML narrative parser unbounded recursion causes StackOverflow denial of service
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
HAPI FHIRto a version that resolves this vulnerability.Fixed in 6.9.11
Event History
Frequently Asked Questions
What is the severity of CVE-2026-62296?
The severity of CVE-2026-62296 is rated high with a score of 7.5.
What causes the CVE-2026-62296 vulnerability?
CVE-2026-62296 is caused by unbounded recursion in the XHTML narrative parser of HAPI FHIR that can lead to a StackOverflow denial of service.
How do I fix CVE-2026-62296?
To fix CVE-2026-62296, update HAPI FHIR to version 6.9.11 or later where the issue has been addressed.
What is the impact of CVE-2026-62296 on my system?
The impact of CVE-2026-62296 can lead to a denial of service due to StackOverflow errors caused by deeply nested XHTML elements.
Which versions of HAPI FHIR are affected by CVE-2026-62296?
Versions prior to 6.9.11 of HAPI FHIR are affected by CVE-2026-62296.