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

Advisory record · `GHSA-fgv2-4q4g-wc35`

- **Identifiers:** `GHSA-fgv2-4q4g-wc35` · `CVE-2026-34359`
- **State:** Confirmed
- **Severity:** CVSS 7.4 High
- **Critical:** No
- **Weakness (CWE):** [CWE-346](https://cwe.mitre.org/data/definitions/346.html)
- **Tags:** [CWE-346](https://agentprime.io/advisories/tag/cwe-346.md)
- **Published:** 30 Mar 2026
- **Updated:** 31 Mar 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 30 Mar 2026, 17:19 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `ca.uhn.hapi.fhir:org.hl7.fhir.core` (Maven): affected `<6.9.4`; fixed in `6.9.4`
- `ca.uhn.hapi.fhir:org.hl7.fhir.utilities` (Maven): affected `<6.9.4`; fixed in `6.9.4`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> The HAPI FHIR Core packages org.hl7.fhir.core and org.hl7.fhir.utilities, versions before 6.9.4, match configured server URLs by string prefix when sending authentication credentials. An attacker who can redirect a request to a domain whose name begins with a configured server URL (for example, a lookalike domain appended to a configured terminology server) can receive Bearer tokens, Basic auth credentials, or API keys, and can potentially bypass the HTTPS requirement. Upgrade to version 6.9.4 or later.

Written 3 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.4 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0016, the 5th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:20 UTC: First seen by agentprime
- 31 Oct 2026, 14:20 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-fgv2-4q4g-wc35)

## Sources

- [GitHub Advisory Database: GHSA-fgv2-4q4g-wc35](https://github.com/advisories/GHSA-fgv2-4q4g-wc35)
- [OSV: GHSA-fgv2-4q4g-wc35](https://osv.dev/vulnerability/GHSA-fgv2-4q4g-wc35)
- <https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-fgv2-4q4g-wc35>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-34359>
- <https://github.com/hapifhir/org.hl7.fhir.core>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-fgv2-4q4g-wc35>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-fgv2-4q4g-wc35/>. Everything for agents: <https://agentprime.io/llms.txt>.