HAPI FHIR Core has Authentication Credential Leakage via Improper URL Prefix Matching on HTTP Redirect

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.4 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-34359: 0.16% estimated exploitation activity in the next 30 days; percentile 5.68 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. Details The root cause is in ManagedWebAccessUtils.getServer() at org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/http/ManagedWebAccessUtils.java:26: The configured production terminology server URL is defined without a trailing slash in FhirSettingsPOJO.java:19: This means: - "http://tx.fhir.org.attacker.com/capture".startsWith("http://tx.fhir.org") → true - "http://tx.fhir.org:8080/evil".startsWith("http://tx.fhir.org") → true Exploit chain via SimpleHTTPClient (redirect path): 1. SimpleHTTPClient.get()…

Published by the source

30 Mar 2026, 17:19 UTC

Last modified by the source

31 Mar 2026, 18:55 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fgv2-4q4g-wc35

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# Patch Next advisory brief: CVE-2026-34359

Advisory: HAPI FHIR Core has Authentication Credential Leakage via Improper URL Prefix Matching on HTTP Redirect
IDs: CVE-2026-34359, GHSA-fgv2-4q4g-wc35
Record: https://patchnext.com/advisories/cve-2026-34359 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: ca.uhn.hapi.fhir:org.hl7.fhir.utilities 6.9.4; ca.uhn.hapi.fhir:org.hl7.fhir.core 6.9.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven ca.uhn.hapi.fhir:org.hl7.fhir.utilities: affected < 6.9.4; fixed in 6.9.4
- Maven ca.uhn.hapi.fhir:org.hl7.fhir.core: affected < 6.9.4; fixed in 6.9.4

## Suggested inspection (read-only)
- Maven ca.uhn.hapi.fhir:org.hl7.fhir.utilities: check the installed version with your package manager.
- Maven ca.uhn.hapi.fhir:org.hl7.fhir.core: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on ca.uhn.hapi.fhir:org.hl7.fhir.utilities, ca.uhn.hapi.fhir:org.hl7.fhir.core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-fgv2-4q4g-wc35 (GitHub-reviewed advisory GHSA-fgv2-4q4g-wc35 lists affected ranges: Maven ca.uhn.hapi.fhir:org.hl7.fhir.core >=0 =0 <6.9.4)

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