# CVE-2026-55471: HAPI FHIR: XXE in XsltUtilities.saxonTransform via unhardened Saxon TransformerFactory


- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 8 Jul 2026
- **Updated:** 9 Jul 2026
- **Also known as:** GHSA-2f55-g35j-5jmf, ROOT-APP-MAVEN-CVE-2026-55471

## What is CVE-2026-55471?

CVE-2026-55471 is a high-severity vulnerability in hapifhir org.hl7.fhir.core, published on 8 Jul 2026. 

### Official description

HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.10, org.hl7.fhir.utilities.XsltUtilities saxonTransform(...) overloads instantiated a bare net.sf.saxon.TransformerFactoryImpl() without ACCESS_EXTERNAL_DTD or ACCESS_EXTERNAL_STYLESHEET restrictions, allowing an attacker who controls or can tamper with transformed XML to trigger XML External Entity injection for local file disclosure and blind XXE or SSRF to arbitrary URLs reachable from the host. This issue is fixed in version 6.9.10.

Weakness: CWE-611 (Improper Restriction of XML External Entity Reference)

## Which versions are affected by CVE-2026-55471?

2 open source packages ship an affected version, including ca.uhn.hapi.fhir:org.hl7.fhir.utilities. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ca.uhn.hapi.fhir:org.hl7.fhir.utilities` | Maven | All versions | 6.9.10 |
| `ca.uhn.hapi.fhir:org.hl7.fhir.utilities` | Maven | All versions | 6.9.10 |

Products: Hapifhir Hl7 Fhir Core.

## How do I fix CVE-2026-55471?

Upgrade ca.uhn.hapi.fhir:org.hl7.fhir.utilities to 6.9.10 or later.

## Is CVE-2026-55471 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55471 exists.

## Other vulnerabilities in hapifhir org.hl7.fhir.core

- [CVE-2026-34361](https://insights.sbomify.com/CVE-2026-34361/): HAPI FHIR: Unauthenticated SSRF via /loadIG Chains with startsWith() Credential Leak for Authentication Token Theft (critical 9.3)
- [CVE-2023-24057](https://insights.sbomify.com/CVE-2023-24057/): MITM based Zip Slip in `ca.uhn.hapi.fhir:org.hl7.fhir.core` (high 8.1)
- [CVE-2026-55470](https://insights.sbomify.com/CVE-2026-55470/): HAPI FHIR: DSTU2 FHIRPathEngine.matches() missing RegexTimeout protection allows ReDoS (high 7.5)
- [CVE-2023-28465](https://insights.sbomify.com/CVE-2023-28465/): HL7 FHIR Partial Path Zip Slip due to bypass of CVE-2023-24057 (high 7.5)
- [CVE-2026-34359](https://insights.sbomify.com/CVE-2026-34359/): HAPI FHIR: Authentication Credential Leakage via Improper URL Prefix Matching on HTTP Redirect in HAPI FHIR Core (high 7.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55471 and fix it if it is affected.

What it is: CVE-2026-55471 is a high-severity vulnerability in hapifhir org.hl7.fhir.core, published on 8 Jul 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55471 exists.

Affected packages and fixed versions:
- ca.uhn.hapi.fhir:org.hl7.fhir.utilities (Maven): affected all versions; fixed in 6.9.10
- ca.uhn.hapi.fhir:org.hl7.fhir.utilities (Maven): affected all versions; fixed in 6.9.10

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-55471/ (Markdown: https://insights.sbomify.com/CVE-2026-55471/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55471
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55471
- OSV: https://osv.dev/vulnerability/CVE-2026-55471

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55471/
Summaries are generated and may contain mistakes; the official description above is the record.