CVE-2026-55471
XXE/SSRF in HAPI FHIR XML transformer allowing local file disclosure and SSRF.
Is CVE-2026-55471 being exploited?
Not confirmed. CVE-2026-55471 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.57% probability of exploitation in the next 30 days.
How severe is CVE-2026-55471?
CVE-2026-55471 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-55471?
Yes. A fix has been recorded for CVE-2026-55471. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-55471 affect?
CVE-2026-55471 affects HAPI FHIR < 6.9.10, org.hl7.fhir.utilities.XsltUtilities.saxonTransform, net.sf.saxon.TransformerFactoryImpl. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-55471?
Upgrade to HAPI FHIR 6.9.10; validate/untrusted XML and disable external DTD/stylesheet access.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
XXE via Saxon transformer enables local file disclosure, blind XXE and SSRF to arbitrary URLs reachable from the host.
Patch when possible
- affected< 6.9.10
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.