CVE-2026-55471: HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java

Q: How do I fix CVE-2026-55471?

hl7 fhir core: upgrade to 6.9.10. Exact commands for each OS are on this page.

Q: Is CVE-2026-55471 being exploited?

CVE-2026-55471 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-55471 affect?

CVE-2026-55471 affects hl7 fhir core. Severity is critical (CVSS 9.1). 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.TransformerFactory

Q: How urgent is CVE-2026-55471?

Priority 54/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.1REMOTEUPGRADE

CVE-2026-55471 is a critical-severity flaw (CVSS 9.1) affecting hl7 fhir core. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 disclo

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 53%)
CISA exploited list	No
Weakness	CWE-611
Published	2026-07-08
Last modified	2026-10-25

Publisher (CNA): GitHub, Inc. · Vendor: hapifhir

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-08 22:17 UTCPublished CVE record published
2026-10-25 17:10 UTCUpdated Record last modified

hapifhir hl7 fhir core UPGRADE

Affected: < 6.9.10

Fixed in: 6.9.10

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy hl7-fhir-core || rpm -q hl7-fhir-core || hl7-fhir-core --version

2. UPGRADE to 6.9.10 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade hl7-fhir-core

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade hl7-fhir-core

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-55471?

hl7 fhir core: upgrade to 6.9.10. Exact commands for each OS are on this page.

Is CVE-2026-55471 being exploited?

CVE-2026-55471 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-55471 affect?

CVE-2026-55471 affects hl7 fhir core. Severity is critical (CVSS 9.1). 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.TransformerFactory

How urgent is CVE-2026-55471?

Priority 54/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Java vulnerabilities

Related CVEs

CVE-2026-55470 HIGH 7.5 UPGRADE HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java

References

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