CVE-2026-62296Public exploitNetwork attack vectorHinoki check available

Worker-thread crash via unbounded XHTML parser recursion

Published Aug 7, 2026 · Updated Aug 7, 2026

Uncontrolled recursion in HAPI FHIR before 6.9.11 allows remote attackers to crash a parsing or validation worker thread. XhtmlParser.parseElementInner() and parseElement() mutually recurse over untrusted text.div nesting without maintaining a depth limit. Reachability requires an application or validator service to parse attacker-supplied FHIR JSON or XML; the demonstrated consequence is worker-thread failure and possible process instability.

CVSS severity7.5
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Uncontrolled recursion in HAPI FHIR before 6.9.11 allows remote attackers to crash a parsing or validation worker thread. XhtmlParser.parseElementInner() and parseElement() mutually recurse over untrusted text.div nesting without maintaining a depth limit. Reachability requires an application or validator service to parse attacker-supplied FHIR JSON or XML; the demonstrated consequence is worker-thread failure and possible process instability.

The record

CVE
CVE-2026-62296
Published
Aug 7, 2026
Updated
Aug 7, 2026
Vendor
HAPI FHIR
Product
org.hl7.fhir.r5
Classifications
CWE-20, CWE-400, CWE-674, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6.9.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

HAPI FHIR · org.hl7.fhir.r5version=< 6.9.11
HAPI FHIR · org.hl7.fhir.validationversion=< 6.9.11
HAPI FHIR · org.hl7.fhir.utilitiesversion=< 6.9.11
HAPI FHIR · org.hl7.fhir.validation.cliversion=< 6.9.11
HAPI FHIR · org.hl7.fhir.coreversion=< 6.9.11

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-400Uncontrolled Resource Consumption
CWE-674Uncontrolled Recursion
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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