CVE-2026-34359 HAPI FHIR: Authentication Credential Leakage via Improper URL Prefix Matching on HTTP Redirect in HAPI FHIR Core
Attackers can steal authentication credentials by exploiting improper URL prefix matching during HTTP redirects in the HAPI FHIR library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-34359?
CVE-2026-34359 is a high-severity vulnerability in hapifhir org.hl7.fhir.core, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.4, ManagedWebAccessUtils.getServer() uses String.startsWith() to match request URLs against configured server URLs for authentication credential dispatch. Because configured server URLs (e.g., http://tx.fhir.org) lack a trailing slash or host boundary check, an attacker-controlled domain like http://tx.fhir.org.attacker.com matches the prefix and receives Bearer tokens, Basic auth credentials, or API keys when the HTTP client follows a redirect to that domain. This issue has been patched in version 6.9.4.
Weakness: CWE-346
Which versions are affected by CVE-2026-34359?
4 open source packages ship an affected version, including ca.uhn.hapi.fhir:org.hl7.fhir.core and ca.uhn.hapi.fhir:org.hl7.fhir.utilities. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
ca.uhn.hapi.fhir:org.hl7.fhir.core Maven | All versions | 6.9.4 |
ca.uhn.hapi.fhir:org.hl7.fhir.core Maven | All versions | 6.9.4 |
ca.uhn.hapi.fhir:org.hl7.fhir.utilities Maven | All versions | 6.9.4 |
ca.uhn.hapi.fhir:org.hl7.fhir.utilities Maven | All versions | 6.9.4 |
Products include Hapifhir Hl7 Fhir Core.
How do I fix CVE-2026-34359?
Upgrade ca.uhn.hapi.fhir:org.hl7.fhir.core to 6.9.4 or later.
Is CVE-2026-34359 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34359 exists.
Other vulnerabilities in hapifhir org.hl7.fhir.core
- CVE-2026-34361 HAPI FHIR: Unauthenticated SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft
- CVE-2026-55471 HAPI FHIR: XXE in XsltUtilities.saxonTransform via unhardened Saxon TransformerFactory
- CVE-2023-24057 MITM based Zip Slip in `ca.uhn.hapi.fhir:org.hl7.fhir.core`
- CVE-2026-55470 HAPI FHIR: DSTU2 FHIRPathEngine.matches() missing RegexTimeout protection allows ReDoS
- CVE-2023-28465 HL7 FHIR Partial Path Zip Slip due to bypass of CVE-2023-24057
Sources
Also known as GHSA-fgv2-4q4g-wc35, ROOT-APP-MAVEN-CVE-2026-34359.