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Fencer Vulns
high 7.5

CVE-2026-55470 json

HAPI FHIR: DSTU2 FHIRPathEngine.matches() missing RegexTimeout protection allows ReDoS

published 2026-06-17 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-42440 , GHSA-fxj4-p9xp-37v5

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits
0
none known

Summary

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.

Patch / fix

  • maven ca.uhn.hapi.fhir:org.hl7.fhir.dstu2 6.9.10
  • maven ca.uhn.hapi.fhir:org.hl7.fhir.convertors 6.9.10
  • maven ca.uhn.hapi.fhir:org.hl7.fhir.validation 6.9.10
  • maven ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli 6.9.10
  • ca.uhn.hapi.fhir org.hl7.fhir.core 6.9.10
  • hapifhir hl7_fhir_core 6.9.10

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-55470 updated cvss 7.5

ca.uhn.hapi.fhir/org.hl7.fhir.dstu2: ca.uhn.hapi.fhir/org.hl7.fhir.convertors: ca.uhn.hapi.fhir/org.hl7.fhir.validation: ca.uhn.hapi.fhir/org.hl7.fhir.validation.cli: HAPI FHIR: Denial of Service via

  • Red Hat build of Apache Camel 4 for Quarkus 3 org.hl7.fhir.dstu2 6.6.7
    affected: workaround, no fix available
  • Red Hat Build of Apache Camel 4.18 for Quarkus 3.33
    fixed: vendor fix RHSA-2026:54776
  • Red Hat JBoss Enterprise Application Platform Expansion Pack org.hl7.fhir.dstu2 6.6.7
    not affected: component not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.68% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-fxj4-p9xp-37v5 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
maven ca.uhn.hapi.fhir:org.hl7.fhir.dstu2
<6.9.10
6.9.10
maven ca.uhn.hapi.fhir:org.hl7.fhir.convertors
<6.9.10
6.9.10
maven ca.uhn.hapi.fhir:org.hl7.fhir.validation
<6.9.10
6.9.10
maven ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli
<6.9.10
6.9.10

Affected products

  • hapifhir org.hl7.fhir.core

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.