# CVE-2026-55471: HAPI FHIR XXE injection in XsltUtilities saxonTransform

Source: https://junglewise.ai/threats/cve-2026-55471-hapi-fhir-xxe-injection-in-xsltutilities-saxontransform  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-08. Updated: 2026-07-08  
License: CC BY 4.0 with a link back

CVE-2026-55471 · Severity: critical · CVSS 4 · Published 2026-07-08

HAPI FHIR is a Java library used to implement healthcare data standards for interoperability. A security flaw in its XML processing component allows an attacker to read sensitive local files or perform unauthorized network requests by providing a specially crafted XML document. This could lead to the exposure of confidential patient data or internal system information.

Technologies: [ca.uhn.hapi.fhir:org.hl7.fhir.utilities (Maven)](https://junglewise.ai/threats/technologies/ca-uhn-hapi-fhir-org-hl7-fhir-utilities). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven).

## Quick answers

**Is CVE-2026-55471 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55471 being exploited in the wild.

**How severe is CVE-2026-55471?** Critical severity, with a CVSS score of 4, published 8 July 2026.

**Which products and versions are affected?** HAPI FHIR Core Utilities <= 6.9.9; ca.uhn.hapi.fhir:org.hl7.fhir.utilities (Maven) <= 6.9.9, ECOSYSTEM:introduced=0,fixed=6.9.10.

**Is there a fix for CVE-2026-55471?** Yes. ca.uhn.hapi.fhir:org.hl7.fhir.utilities (Maven): upgrade to 6.9.10 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-55471 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-55471?** Check whether you run HAPI FHIR Core Utilities or ca.uhn.hapi.fhir:org.hl7.fhir.utilities (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- ca.uhn.hapi.fhir:org.hl7.fhir.utilities (Maven): upgrade to 6.9.10 or later

  ```sh
  # set ca.uhn.hapi.fhir:org.hl7.fhir.utilities to 6.9.10 in your pom.xml or build.gradle
  ```


## Technical details

The vulnerability exists in the `org.hl7.fhir.utilities.XsltUtilities` class, specifically within the `saxonTransform(...)` overloads. These methods instantiate a `net.sf.saxon.TransformerFactoryImpl` without disabling external DTDs or external stylesheets (missing `ACCESS_EXTERNAL_DTD` and `ACCESS_EXTERNAL_STYLESHEET` restrictions). An attacker who can influence the XML source, DTD, or stylesheet processed by these methods can trigger an XXE injection. This can be exploited for local file disclosure, blind XXE, or SSRF against internal network resources. The issue was resolved in version 6.9.10 by ensuring the Saxon factory is properly hardened.

## Affected products

- hapifhir org.hl7.fhir.core < 6.9.10

## Identifiers

- CVE-2026-55471
- GHSA-2f55-g35j-5jmf

## Timeline

- 2026-06-12: patched: Version 6.9.10 released
- 2026-06-17: advisory: GitHub Security Advisory published
- 2026-07-08: disclosed: CVE published to NVD

## References

- [https://github.com/hapifhir/org.hl7.fhir.core/commit/01ca2ecdefec9b33204d2495fe78af8c0dc52298](https://github.com/hapifhir/org.hl7.fhir.core/commit/01ca2ecdefec9b33204d2495fe78af8c0dc52298)
- [https://github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.10](https://github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.10)
- [https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-2f55-g35j-5jmf](https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-2f55-g35j-5jmf)

## Related threats

- [HAPI FHIR credential leakage via improper URL prefix matching](https://junglewise.ai/threats/cve-2026-34359-hapi-fhir-credential-leakage-via-improper-url-prefix-matching)
- [HAPI FHIR sensitive information leak via HTTP redirects](https://junglewise.ai/threats/cve-2026-33180-hapi-fhir-sensitive-information-leak-via-http-redirects)
- [XXE vulnerability in XSLT parsing in `org.hl7.fhir.core`](https://junglewise.ai/threats/cve-2024-52007-xxe-vulnerability-in-xslt-parsing-in-org-hl7-fhir-core)
- [HAPI FHIR XML External Entity (XXE) vulnerability](https://junglewise.ai/threats/cve-2024-51132-hapi-fhir-xml-external-entity-xxe-vulnerability)
- [XXE vulnerability in XSLT transforms in `org.hl7.fhir.core`](https://junglewise.ai/threats/cve-2024-45294-xxe-vulnerability-in-xslt-transforms-in-org-hl7-fhir-core)