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TI-2026-44484 Aliases CVE-2026-62295

HAPI FHIR: JSON utility parser unbounded recursion causes StackOverflow denial of service

Priority HIGH 72CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-400.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00488 42nd percentileScored 2026-11-07
Fix Fixed org.hl7.fhir.core (hapifhir): 6.9.11ca.uhn.hapi.fhir:org.hl7.fhir.r5 (hapifhir): 6.9.11+3 more products

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
hapifhirorg.hl7.fhir.corebefore 6.9.116.9.11Patch availableCNA
hapifhirca.uhn.hapi.fhir:org.hl7.fhir.r5before 6.9.116.9.11Patch availableCNA
hapifhirca.uhn.hapi.fhir:org.hl7.fhir.utilitiesbefore 6.9.116.9.11Patch availableCNA
hapifhirca.uhn.hapi.fhir:org.hl7.fhir.validationbefore 6.9.116.9.11Patch availableCNA
hapifhirca.uhn.hapi.fhir:org.hl7.fhir.validation.clibefore 6.9.116.9.11Patch availableCNA
  • org.hl7.fhir.core Vendorhapifhir Affected before 6.9.11 Fixed in 6.9.11 Patch available CNA
  • ca.uhn.hapi.fhir:org.hl7.fhir.r5 Vendorhapifhir Affected before 6.9.11 Fixed in 6.9.11 Patch available CNA
  • ca.uhn.hapi.fhir:org.hl7.fhir.utilities Vendorhapifhir Affected before 6.9.11 Fixed in 6.9.11 Patch available CNA
  • ca.uhn.hapi.fhir:org.hl7.fhir.validation Vendorhapifhir Affected before 6.9.11 Fixed in 6.9.11 Patch available CNA
  • ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli Vendorhapifhir Affected before 6.9.11 Fixed in 6.9.11 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:hapifhir:hl7_fhir_core:*:*:*:*:*:*:*:*——hapifhir
  • cpe:2.3:a:hapifhir:hl7_fhir_core:*:*:*:*:*:*:*:* Versions — — ·hapifhir

Remediation

  • Fix · CNA org.hl7.fhir.core (hapifhir) Fixed in 6.9.11
  • Fix · CNA ca.uhn.hapi.fhir:org.hl7.fhir.r5 (hapifhir) Fixed in 6.9.11
  • Fix · CNA ca.uhn.hapi.fhir:org.hl7.fhir.utilities (hapifhir) Fixed in 6.9.11
  • Fix · CNA ca.uhn.hapi.fhir:org.hl7.fhir.validation (hapifhir) Fixed in 6.9.11
  • Fix · CNA ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli (hapifhir) Fixed in 6.9.11

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-62295

References

Other 2

  • TI-2026-26647 HAPI FHIR: Unauthenticated SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft CVSS 3.1CRITICAL 9.3
  • TI-2026-40028 HAPI FHIR: XXE in XsltUtilities.saxonTransform via unhardened Saxon TransformerFactory CVSS 4.0HIGH 8.7
  • TI-2026-26645 HAPI FHIR: Authentication Credential Leakage via Improper URL Prefix Matching on HTTP Redirect in HAPI FHIR Core CVSS 3.1CRITICAL 9.1
  • TI-2026-56488 HAPI FHIR: SHCParser DEFLATE infinite loop causes denial of service CVSS 3.1HIGH 7.5
  • TI-2026-56487 HAPI FHIR: SHCParser unbounded DEFLATE decompression causes denial of service CVSS 3.1HIGH 7.5
  • TI-2026-44485 HAPI FHIR: XHTML narrative parser unbounded recursion causes StackOverflow denial of service CVSS 3.1HIGH 7.5
See all 17 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences