HAPI FHIR: SHCParser unbounded DEFLATE decompression causes denial of service

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-81875
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 19:17:44 UTC
Updated2026-09-17 17:16:48 UTC
DescriptionHAPI 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 consume attacker-controlled Smart Health Card JWT content whose header contains zip: "DEF" and whose small raw-DEFLATE payload expands to a very large value. SHCParser.decodeJWT() passes the decoded payload to SHCParser.inflate(), which accumulates all decompressed bytes in a ByteArrayOutputStream without an output-size limit before JSON parsing, and SHCParser.decompress() contains the same unbounded pattern. An application or validator service that accepts attacker-supplied SHC content can therefore suffer excessive heap allocation, severe garbage-collection pressure, request failure, process instability, or process termination. This issue is fixed in version 6.9.12.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-20 | CWE-400 | CWE-409 | CWE-20 CWE-20: Improper Input Validation | CWE-400 CWE-400: Uncontrolled Resource Consumption | CWE-409 CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Hapifhir Org.hl7.fhir.core affected < 6.9.12 Not specified

References

ReferenceSourceLinkTags
github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.11 [email protected] github.com
github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.12 [email protected] github.com
github.com/hapifhir/org.hl7.fhir.core/pull/2493 [email protected] github.com
github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-3w98-rrpr... 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/hapifhir/org.hl7.fhir.core/commit/fbb94216e0ad21ded75be77e5e2... [email protected] github.com
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