CVE-2026-62295: HAPI FHIR: JSON utility 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, the JSON utility parser in org.hl7.fhir.utilities.json.parser.JsonParser enforces no maximum nesting depth for arrays or objects. As a result, a small but deeply nested, syntactically valid FHIR JSON document can trigger unbounded readArray() or readObject() recursion, raising a StackOverflowError before structural validation runs. An attacker who can submit JSON resources for validation can thus crash the request thread, and services that do not isolate StackOverflowError safely may experience worker loss or process instability — a denial-of-service condition. This issue is fixed in version 6.9.11.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
HAPI FHIR (org.hl7.fhir.utilities.json.parser.JsonParser)to a version that resolves this vulnerability.Fixed in 6.9.11
Event History
Frequently Asked Questions
What is the severity of CVE-2026-62295?
The severity of CVE-2026-62295 is high, rated at 7.5.
What does CVE-2026-62295 affect?
CVE-2026-62295 affects the HAPI FHIR software, specifically the JSON utility parser.
How can CVE-2026-62295 be exploited?
CVE-2026-62295 can be exploited through unbounded recursion in deeply nested JSON objects or arrays, leading to a StackOverflow denial of service.
What versions of HAPI FHIR are impacted by CVE-2026-62295?
Versions prior to 6.9.11 of HAPI FHIR are impacted by CVE-2026-62295.
How do I fix CVE-2026-62295?
To fix CVE-2026-62295, upgrade to HAPI FHIR version 6.9.11 or later.