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CVE-2026-81876GHSA-GQ9C-WMRM-5HVR

HAPI FHIR: SHCParser DEFLATE infinite loop causes denial of service

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 6.9.12
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: yes
  • Technical impact: partial

Summary

HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to version 6.9.12, SHCParser in org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/elementmodel/SHCParser.java can enter an infinite loop while processing attacker-controlled Smart Health Card JWT content whose header contains zip: "DEF" and whose raw-DEFLATE payload is empty or truncated. SHCParser.decodeJWT() reaches SHCParser.inflate(), where Inflater.inflate() can return zero while Inflater.finished() remains false and Inflater.needsInput() is true. The loop also lacks an Inflater.needsDictionary() termination check, SHCParser.decompress() contains the same zero-progress pattern, and ResourceChecker.java can reach SHC parsing during file-format detection. A malformed validation request can pin a JVM worker thread indefinitely, and concurrent requests can exhaust all validation workers. This issue is fixed in version 6.9.12.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • hapifhir org.hl7.fhir.core

    fixed in 6.9.12

  • ca.uhn.hapi.fhir:org.hl7.fhir.r5Maven

    fixed in 6.9.12

  • ca.uhn.hapi.fhir:org.hl7.fhir.validationMaven

    fixed in 6.9.12

  • ca.uhn.hapi.fhir:org.hl7.fhir.validation.cliMaven

    fixed in 6.9.12

References 4

GitHub · hapifhir/org.hl7.fhir.core