Vulnerability · Published Mar 31, 2026 · Assigned by GitHub_M

CVE-2026-34361HAPI FHIR: Unauthenticated SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft

Critical 9.3

In plain English

A critical-severity security flaw in org.hl7.fhir.core from hapifhir. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.3Critical

Exploit odds (30 days)0.3%top 76.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.4, the FHIR Validator HTTP service exposes an unauthenticated "/loadIG" endpoint that makes outbound HTTP requests to attacker-controlled URLs. Combined with a startsWith() URL prefix matching flaw in the credential provider (ManagedWebAccessUtils.getServer()), an attacker can steal authentication tokens (Bearer, Basic, API keys) configured for legitimate FHIR servers by registering a domain that prefix-matches a configured server URL. This issue has been patched in version 6.9.4.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Maven	ca.uhn.hapi.fhir:org.hl7.fhir.validation	6.9.4	GHSA-vr79-8m62-wh98

Affected products (as reported)

Vendor	Product	Versions
hapifhir	org.hl7.fhir.core	< 6.9.4

Weakness: CWE-552 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

References

https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-vr79-8m62-wh98 x_refsource_CONFIRM