Ca.uhn.hapi.fhir:org.hl7.fhir.dstu2: CWE-1333: Inefficient Regular Expression Complexity in hapifhir org.hl7.fhir.core (CVE-2026-49485)
HAPI FHIR versions prior to 6.9.4.2 and between 6.9.5 and before 6.9.9 contain a vulnerability in the FHIRPathEngine where user-supplied regular expressions are evaluated without sufficient input validation. The functions matches(), matchesFull(), and replaceMatches() use these regex patterns with an incomplete timeout mechanism, allowing crafted regex patterns to cause catastrophic backtracking. This results in excessive CPU consumption and denial of service in the FHIR Validator HTTP endpoint and related modules. The issue is fixed in versions 6.9.9 and 6.9.4.2.
AI Analysis
Technical Summary
The vulnerability CVE-2026-49485 affects the HAPI FHIR org.hl7.fhir.core library's FHIRPathEngine implementation. It improperly handles user-controlled regular expressions passed to Java's Pattern.compile() and String.replaceAll() functions via the matches(), matchesFull(), and replaceMatches() methods. Due to incomplete timeout handling, specially crafted regex patterns can cause catastrophic backtracking, leading to CPU exhaustion and denial of service conditions. This impacts the FHIR Validator HTTP endpoint and other org.hl7.fhir.* modules. The vulnerability is resolved in versions 6.9.9 and 6.9.4.2.
Potential Impact
An attacker can exploit this vulnerability by submitting FHIR resources containing malicious regular expressions that trigger catastrophic backtracking during regex evaluation. This causes high CPU usage and denial of service in the affected components, specifically the FHIR Validator HTTP endpoint and related modules. There is no impact on confidentiality or integrity reported. The CVSS v3.1 score is 7.5 (High), reflecting network attack vector, low complexity, no privileges required, no user interaction, and impact limited to availability.
Mitigation Recommendations
This vulnerability is fixed in HAPI FHIR versions 6.9.9 and 6.9.4.2. Users should upgrade to one of these versions or later to remediate the issue. Since this is not a cloud service, remediation depends on applying these official fixes. Patch status is confirmed by the vendor advisory. No additional mitigations are specified.
Ca.uhn.hapi.fhir:org.hl7.fhir.dstu2: CWE-1333: Inefficient Regular Expression Complexity in hapifhir org.hl7.fhir.core (CVE-2026-49485)
Description
HAPI FHIR versions prior to 6.9.4.2 and between 6.9.5 and before 6.9.9 contain a vulnerability in the FHIRPathEngine where user-supplied regular expressions are evaluated without sufficient input validation. The functions matches(), matchesFull(), and replaceMatches() use these regex patterns with an incomplete timeout mechanism, allowing crafted regex patterns to cause catastrophic backtracking. This results in excessive CPU consumption and denial of service in the FHIR Validator HTTP endpoint and related modules. The issue is fixed in versions 6.9.9 and 6.9.4.2.
CVSS v3.1
Score 7.5high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-49485 affects the HAPI FHIR org.hl7.fhir.core library's FHIRPathEngine implementation. It improperly handles user-controlled regular expressions passed to Java's Pattern.compile() and String.replaceAll() functions via the matches(), matchesFull(), and replaceMatches() methods. Due to incomplete timeout handling, specially crafted regex patterns can cause catastrophic backtracking, leading to CPU exhaustion and denial of service conditions. This impacts the FHIR Validator HTTP endpoint and other org.hl7.fhir.* modules. The vulnerability is resolved in versions 6.9.9 and 6.9.4.2.
Potential Impact
An attacker can exploit this vulnerability by submitting FHIR resources containing malicious regular expressions that trigger catastrophic backtracking during regex evaluation. This causes high CPU usage and denial of service in the affected components, specifically the FHIR Validator HTTP endpoint and related modules. There is no impact on confidentiality or integrity reported. The CVSS v3.1 score is 7.5 (High), reflecting network attack vector, low complexity, no privileges required, no user interaction, and impact limited to availability.
Mitigation Recommendations
This vulnerability is fixed in HAPI FHIR versions 6.9.9 and 6.9.4.2. Users should upgrade to one of these versions or later to remediate the issue. Since this is not a cloud service, remediation depends on applying these official fixes. Patch status is confirmed by the vendor advisory. No additional mitigations are specified.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-7cmj-v6x8-frvv
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-49485"]
- Ecosystems
- ["Maven"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a50bac868715ace435892aa
Added to database: 07/10/2026, 09:26:32 UTC
Last enriched: 07/18/2026, 11:17:55 UTC
Last updated: 07/19/2026, 05:26:46 UTC
Views: 47
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