How severe is CVE-2026-55471?

CVE-2026-55471 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-55471 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-55471?

CVE-2026-55471 affects Hapifhir Hl7 Fhir Core. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-55471?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-55471 published?

CVE-2026-55471 was published on 2026-07-08 and last updated on 2026-07-16.

CVE-2026-55471

CVE-2026-55471 is a critical-severity vulnerability in Hapifhir Hl7 Fhir Core with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-611.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v4: 8.7
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-611
Affected product: Hapifhir Hl7 Fhir Core
Published: 2026-07-08
Last modified: 2026-07-16

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.

Frequently asked questions

What is CVE-2026-55471?: 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.
How severe is CVE-2026-55471?: CVE-2026-55471 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-55471 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-55471?: CVE-2026-55471 affects Hapifhir Hl7 Fhir Core. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-55471?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-55471 published?: CVE-2026-55471 was published on 2026-07-08 and last updated on 2026-07-16.

References

Affected products (1)

cpe:2.3:a:hapifhir:hl7_fhir_core:*:*:*:*:*:*:*:*

More vulnerabilities in Hapifhir Hl7 Fhir Core

CVE-2026-34361 — Critical (CVSS 9.3): HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to…
CVE-2023-24057 — High (CVSS 8.1): HL7 (Health Level 7) FHIR Core Libraries before 5.6.92 allow attackers to extract files into arbitrary directories via…
CVE-2026-55470 — High (CVSS 7.5): HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to…
CVE-2023-28465 — High (CVSS 7.5): The package-decompression feature in HL7 (Health Level 7) FHIR Core Libraries before 5.6.106 allows attackers to copy…
CVE-2026-34359 — High (CVSS 7.4): HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to…
CVE-2026-34360 — Medium (CVSS 5.8): HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to…

All CVEs affecting Hapifhir Hl7 Fhir Core →

Other CWE-611 (Improper Restriction of XML External Entity Reference (XXE)) vulnerabilities

CVE-2022-22486 — Critical (CVSS 10.0): IBM Tivoli Workload Scheduler 9.4, 9.5, and 10.1 is vulnerable to an XML External Entity Injection (XXE) attack when…
CVE-2019-14678 — Critical (CVSS 10.0): SAS XML Mapper 9.45 has an XML External Entity (XXE) vulnerability that can be leveraged by malicious attackers in…
CVE-2015-9280 — Critical (CVSS 10.0): MailEnable before 8.60 allows XXE via an XML document in the request.aspx Options parameter.
CVE-2018-1000838 — Critical (CVSS 10.0): autopsy version <= 4.9.0 contains a XML External Entity (XXE) vulnerability in CaseMetadata XML Parser that can result…
CVE-2018-1000837 — Critical (CVSS 10.0): UML Designer version <= 8.0.0 contains a XML External Entity (XXE) vulnerability in XML parser for plugins that can…
CVE-2018-1000835 — Critical (CVSS 10.0): KeePassDX version <= 2.5.0.0beta17 contains a XML External Entity (XXE) vulnerability in kdbx file parser that can…

Browse all CWE-611 (Improper Restriction of XML External Entity Reference (XXE)) vulnerabilities →