CVE-2026-49485

HAPI FHIR: ReDoS via FHIRPath matches()/replaceMatches() in FHIR Validator HTTP Endpoint

State
Published
Severity
7.5 High
Published
Jul 17, 2026
Updated
Jul 20, 2026
Reserved
May 30, 2026

Read the record on cve.org

Description

HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.9 and 6.9.4.2, all implementations of FHIRPathEngine accept arbitrary FHIRPath expressions and evaluate them without input validation, and the FHIRPath functions matches(), matchesFull(), and replaceMatches() pass user-controlled regular expressions to Java's Pattern.compile() and String.replaceAll() through an incomplete timeout utility. An attacker can send a resource containing an evil regex pattern that causes catastrophic backtracking, exhausting CPU resources and causing denial of service in the FHIR Validator HTTP endpoint and affected org.hl7.fhir.* modules. This issue is fixed in versions 6.9.9 and 6.9.4.2.

Scores

CVSSScoreVectorSource
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HGitHub_M

Weaknesses

  • CWE-1333 Inefficient Regular Expression Complexity
  • CWE-400 Uncontrolled Resource Consumption

Affected Products

ProductVersions
org.hl7.fhir.corehapifhir
  • < 6.9.4.2Affected
  • >= 6.9.5, < 6.9.9Affected

References

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