---
cve: "CVE-2026-81876"
severity: "HIGH"
cvss: 7.5
epss: "0.6%"
vendor: "hapifhir"
kev: false
exploited: false
published: "2026-09-16 19:17:44"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-10-23T17:32:11+02:00"
---

# CVE-2026-81876

> 7.5 HIGH · 🧪 PoC

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **GitHub_M**
- State: PUBLISHED
- Stand: 2026-09-17 14:02:56
- CNA-CVSS: **7.5** (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **poc**
  - Automatable: **yes**
  - Technical Impact: **partial**

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Schwachstellen-Klasse

- **CWE-20** — Improper Input Validation
  The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- **CWE-400** — Uncontrolled Resource Consumption
  The product does not properly control the allocation and maintenance of a limited resource.
- **CWE-835** — Loop with Unreachable Exit Condition ('Infinite Loop')
  The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

## Angriffsmuster (CAPEC)

- [CAPEC-10 — Buffer Overflow via Environment Variables](https://capec.mitre.org/data/definitions/10.html) _(Severity: High)_
- [CAPEC-13 — Subverting Environment Variable Values](https://capec.mitre.org/data/definitions/13.html) _(Severity: Very High)_
- [CAPEC-101 — Server Side Include (SSI) Injection](https://capec.mitre.org/data/definitions/101.html) _(Severity: High)_
- [CAPEC-104 — Cross Zone Scripting](https://capec.mitre.org/data/definitions/104.html) _(Severity: High)_
- [CAPEC-108 — Command Line Execution through SQL Injection](https://capec.mitre.org/data/definitions/108.html) _(Severity: Very High)_
- [CAPEC-109 — Object Relational Mapping Injection](https://capec.mitre.org/data/definitions/109.html) _(Severity: High)_
- [CAPEC-110 — SQL Injection through SOAP Parameter Tampering](https://capec.mitre.org/data/definitions/110.html) _(Severity: Very High)_
- [CAPEC-120 — Double Encoding](https://capec.mitre.org/data/definitions/120.html) _(Severity: Medium)_

## ATT&CK-Techniken

- [T1562.003 — Impair Defenses:Impair Command History Logging](https://attack.mitre.org/techniques/T1562/003/)
- [T1574.006 — Hijack Execution Flow:Dynamic Linker Hijacking](https://attack.mitre.org/techniques/T1574/006/)
- [T1574.007 — Hijack Execution Flow:Path Interception by PATH Environment ](https://attack.mitre.org/techniques/T1574/007/)

## Patch verfügbar (OSV)

- 73c432b5f43ddbce979978a760ec4aa81e929094 (Commit)
- d804558bd77372b1629e55a5b901cad3f5134cdc (Commit)

## Referenzen

- <https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-gq9c-wmrm-5hvr>
- <https://github.com/hapifhir/org.hl7.fhir.core/pull/2493>
- <https://github.com/hapifhir/org.hl7.fhir.core/commit/d804558bd77372b1629e55a5b901cad3f5134cdc>
- <https://github.com/hapifhir/org.hl7.fhir.core/commit/edd5d8c139e669e39270785f08be7b63aefef24c>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-81876/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_