Bug 2512644 (CVE-2026-62296)

Summary: CVE-2026-62296 ca.uhn.hapi.fhir/hapi-fhir-base: HAPI FHIR: Denial of Service via unbounded recursion in XHTML narrative parser
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: anujha, asoldano, bbaranow, bmaxwell, bstansbe, dlofthou, fmongiar, istudens, ivassile, iweiss, janstey, jnethert, mosmerov, msvehla, nwallace, pberan, pesilva, pjindal, pmackay, rstancel, thjenkin, vdosoudi
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in HAPI FHIR, a Java implementation of the HL7 FHIR standard. The XHTML narrative parser does not limit element nesting depth, which allows a deeply nested narrative to trigger unbounded recursion. A remote attacker can exploit this vulnerability by submitting FHIR resources containing such narratives, leading to a StackOverflowError. This can crash a parsing or validation worker thread, resulting in a Denial of Service (DoS) for validator services and applications processing attacker-supplied FHIR JSON or XML.
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Description OSIDB Bzimport 2026-08-07 20:21:25 UTC 
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.