CVE-2026-55470Public exploitNetwork attack vector

Unauthenticated CPU exhaustion via unbounded FHIRPath matches

Published Jul 8, 2026 · Updated Jul 8, 2026

Regular expression denial of service in org.hl7.fhir.core before 6.9.10 allows remote attackers to exhaust server CPU via FHIRPath matches(). DSTU2 FHIRPathEngine.funcMatches converts the expression argument to a regex and passes it to raw String.matches without RegexTimeout protection. Unauthenticated submission of a resource or FHIRPath expression with a catastrophically backtracking pattern can monopolize request-processing CPU and disrupt the service.

CVSS severity7.5
High
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Regular expression denial of service in org.hl7.fhir.core before 6.9.10 allows remote attackers to exhaust server CPU via FHIRPath matches(). DSTU2 FHIRPathEngine.funcMatches converts the expression argument to a regex and passes it to raw String.matches without RegexTimeout protection. Unauthenticated submission of a resource or FHIRPath expression with a catastrophically backtracking pattern can monopolize request-processing CPU and disrupt the service.

The record

CVE
CVE-2026-55470
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
HAPI FHIR
Product
org.hl7.fhir.core
Classifications
CWE-1333, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 6.9.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

HAPI FHIR · org.hl7.fhir.coreversion=< 6.9.10

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo