CVE-2026-62296

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

HIGH
7.5
CVSS Score
Published: August 7, 2026 at 08:03 PM UTC
Updated: September 9, 2026 at 09:17 PM UTC
1 product affected across 1 vendorHL7 Fhir Core

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Severity
HIGH7.5
Exploit prediction
EPSS 0.5%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.9.11
Affected range stops below 6.9.11, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-20CWE-400CWE-674

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