Vulnerability in Hapifhir Hl7 Fhir Core
CVE-2026-55470
HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.10, the fix for CVE-2026-45367 incompletely patched the DSTU2 module, leaving FHIRPathEngine.matches() in org.hl7.fhir.dstu2/utils/FHIRPathEngine.java to call raw String.matches(sw) without RegexTimeout protection while replaceMatches() was updated, allowing an unauthenticated attacker to trigger catastrophic regex backtracking and exhaust server CPU. This issue is fixed in version 6.9.10.
Vulnerability class: ReDoS (Regular Expression Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.007 (50.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 50.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000
Affected products
- Hapifhir Hl7 Fhir Core
- Hapifhir Org.hl7.fhir.core — versions < 6.9.10
Weakness classification (CWE)
References
- github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-fxj4-p9xp-37v5 (Exploit, Third Party Advisory)
- github.com/hapifhir/org.hl7.fhir.core/commit/56376f7986222626af061ca7fc27ee1ab0… (Patch)
- github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.10 (Release Notes)
Frequently asked questions
- What is CVE-2026-55470?
- CVE-2026-55470 is a high-severity vulnerability in Hapifhir Hl7 Fhir Core, classified under Inefficient Regular Expression Complexity. CVSS score: 7.5/10. Published 2026-07-08.
- How severe is CVE-2026-55470?
- High severity. CVSS v3 base score is 7.5 out of 10.