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CVE-2026-34361 hapifhir CVE debrief

CVE-2026-34361 is a critical vulnerability in HAPI FHIR, a Java implementation of the HL7 FHIR standard. The FHIR Validator HTTP service exposes an unauthenticated /loadIG endpoint that makes outbound HTTP requests to attacker-controlled URLs. This allows an attacker to steal authentication tokens (Bearer, Basic, API keys) configured for legitimate FHIR servers by registering a domain that prefix-matches a configured server URL. The vulnerability has been patched in version 6.9.4. Healthcare organizations and developers using HAPI FHIR for interoperability should prioritize patching to prevent potential unauthorized access to sensitive healthcare data.

Vendor
hapifhir
Product
org.hl7.fhir.core
CVSS
CRITICAL 9.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-03-31
Original CVE updated
2026-07-24
Advisory published
2026-03-31
Advisory updated
2026-07-24

Who should care

Healthcare organizations and developers using HAPI FHIR for interoperability should prioritize patching to version 6.9.4 or later. This vulnerability allows for the theft of authentication tokens, potentially leading to unauthorized access to sensitive healthcare data. Affected parties should review and update authentication configurations for FHIR servers, implement additional security measures such as token blacklisting and rate limiting, and monitor for suspicious activity related to FHIR server interactions.

Technical summary

The FHIR Validator HTTP service in HAPI FHIR versions prior to 6.9.4 exposes an unauthenticated /loadIG endpoint. This endpoint makes outbound HTTP requests to URLs provided by an attacker. When combined with a flaw in the credential provider (ManagedWebAccessUtils.getServer()), an attacker can register a domain that prefix-matches a configured server URL to steal authentication tokens (Bearer, Basic, API keys) for legitimate FHIR servers. The issue has been addressed in version 6.9.4, which removes the vulnerability by properly securing the /loadIG endpoint.

Defensive priority

High

Recommended defensive actions

  • Patch HAPI FHIR to version 6.9.4 or later
  • Review and update authentication configurations for FHIR servers
  • Monitor for suspicious activity related to FHIR server interactions
  • Implement additional security measures such as token blacklisting and rate limiting
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record was published on 2026-03-31T17:16:32.923Z and last modified on 2026-07-24T20:10:00.147Z. The NVD entry is currently Analyzed. Evidence is limited to public sources and may not reflect the full scope of affected systems or potential impacts. Defenders should verify the official CVE record and NVD entry for the most current information. The unauthenticated /loadIG endpoint vulnerability in HAPI FHIR versions prior to 6.9.4 allows for the theft of authentication tokens, potentially leading to unauthorized access to sensitive healthcare data. This issue has been patched in version 6.9.4.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-03-31T17:16:32.923Z and has not been modified since then. The NVD entry is currently Analyzed.