Quick answers
- Is CVE-2026-55470 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-55470 being exploited in the wild.
- How severe is CVE-2026-55470?
- High severity, with a CVSS score of 7.5, published 8 July 2026.
- Which products and versions are affected?
- ca.uhn.hapi.fhir:org.hl7.fhir.convertors (Maven) <= 6.9.9, ECOSYSTEM:introduced=0,fixed=6.9.10; ca.uhn.hapi.fhir:org.hl7.fhir.dstu2 (Maven) <= 6.9.9, ECOSYSTEM:introduced=0,fixed=6.9.10; ca.uhn.hapi.fhir:org.hl7.fhir.validation (Maven) <= 6.9.9, ECOSYSTEM:introduced=0,fixed=6.9.10; ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli (Maven) <= 6.9.9, ECOSYSTEM:introduced=0,fixed=6.9.10; and 4 more.
- Is there a fix for CVE-2026-55470?
- Yes. ca.uhn.hapi.fhir:org.hl7.fhir.convertors (Maven): upgrade to 6.9.10 or later; ca.uhn.hapi.fhir:org.hl7.fhir.dstu2 (Maven): upgrade to 6.9.10 or later; ca.uhn.hapi.fhir:org.hl7.fhir.validation (Maven): upgrade to 6.9.10 or later; ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli (Maven): upgrade to 6.9.10 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-55470 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-55470?
- Check whether you run ca.uhn.hapi.fhir:org.hl7.fhir.convertors (Maven), ca.uhn.hapi.fhir:org.hl7.fhir.dstu2 (Maven), ca.uhn.hapi.fhir:org.hl7.fhir.validation (Maven) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- ca.uhn.hapi.fhir:org.hl7.fhir.convertors (Maven): upgrade to 6.9.10 or later
# set ca.uhn.hapi.fhir:org.hl7.fhir.convertors to 6.9.10 in your pom.xml or build.gradle - ca.uhn.hapi.fhir:org.hl7.fhir.dstu2 (Maven): upgrade to 6.9.10 or later
# set ca.uhn.hapi.fhir:org.hl7.fhir.dstu2 to 6.9.10 in your pom.xml or build.gradle - ca.uhn.hapi.fhir:org.hl7.fhir.validation (Maven): upgrade to 6.9.10 or later
# set ca.uhn.hapi.fhir:org.hl7.fhir.validation to 6.9.10 in your pom.xml or build.gradle - ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli (Maven): upgrade to 6.9.10 or later
# set ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli to 6.9.10 in your pom.xml or build.gradle
Technical details
The vulnerability is a Regular Expression Denial of Service (ReDoS) caused by an incomplete patch for CVE-2026-45367. While other modules were updated to use 'RegexTimeout' protection, the 'matches()' function in 'org.hl7.fhir.dstu2/utils/FHIRPathEngine.java' continued to call the raw 'String.matches()' method. An unauthenticated attacker can exploit this by submitting a FHIR resource or FHIRPath expression containing a complex regular expression designed to trigger catastrophic backtracking. This results in 100% CPU exhaustion on the host server. The issue is resolved in version 6.9.10 by ensuring all FHIRPath 'matches' calls are time-bounded.
Affected products
- HAPI FHIR org.hl7.fhir.core < 6.9.10
- HAPI FHIR org.hl7.fhir.dstu2 <= 6.9.9
- HAPI FHIR org.hl7.fhir.validation <= 6.9.9
Identifiers
- CVE-2026-55470
- GHSA-fxj4-p9xp-37v5
Timeline
- 2026-06-12: patched: Version 6.9.10 released
- 2026-06-17: advisory: GitHub Security Advisory published
- 2026-07-08: disclosed: CVE-2026-55470 published to NVD