Security readout for executives and security teams
Plain-English summary
This vulnerability can let an unauthenticated remote user make affected HAPI FHIR validation services consume excessive CPU by submitting costly regular expressions through FHIRPath functions. The business impact is service disruption, especially for healthcare systems that expose FHIR validation over HTTP.
Executive priority
Treat as high priority for healthcare interoperability services with exposed validation endpoints. The likely business risk is outage or degraded clinical integration workflows, not confidentiality compromise. Patch promptly where external users can submit validation requests.
Technical view
Before org.hl7.fhir.core 6.9.7, FHIRPathEngine passed user-controlled patterns from matches(), matchesFull(), and replaceMatches() into Java regex operations without effective timeout protection. Catastrophic backtracking can cause denial of service. CVSS 3.1 is 7.5, network reachable, low complexity, no privileges, no user interaction.
Likely exposure
Systems using hapifhir org.hl7.fhir.core below 6.9.7 are exposed, especially if FHIR Validator HTTP endpoints accept untrusted validation requests. Exposure depends on whether those FHIRPath functions are reachable through deployed validation workflows.
Exploitation context
The source bundle does not cite active exploitation, and KEV status is false. The described attack path is remote denial of service through crafted FHIRPath regular expression inputs, not data theft or code execution.
Researcher notes
Evidence supports a ReDoS in FHIRPath regex handling and a fixed release at 6.9.7. The bundle identifies commits and pull requests, but does not establish exploitation in the wild or name additional affected downstream products.
Mitigation direction
- Upgrade hapifhir org.hl7.fhir.core to version 6.9.7 or later.
- Prioritize internet-facing or unauthenticated FHIR Validator HTTP endpoints.
- Restrict access to validation endpoints until the fixed version is deployed.
- Check the GitHub advisory and release notes for vendor-specific guidance.
- Monitor validation services for CPU exhaustion or request latency spikes.
Validation and detection
- Inventory applications and services using org.hl7.fhir.core.
- Confirm dependency versions are 6.9.7 or later in build outputs.
- Identify whether FHIR Validator HTTP endpoints are publicly reachable.
- Review logs for repeated slow or failed validation requests.
- Retest availability after upgrading under normal validation workload.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-1333: Exact CWE lookup
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Open ATT&CK lookupCVE-2026-45367 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6GitHub_MVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-3653-68v6-rq57CVE reference, GitHub_M · x_refsource_CONFIRM
- https://github.com/hapifhir/org.hl7.fhir.core/pull/2403CVE reference, GitHub_M · x_refsource_MISC
- https://github.com/hapifhir/org.hl7.fhir.core/pull/2463CVE reference, GitHub_M · x_refsource_MISC
- https://github.com/hapifhir/org.hl7.fhir.core/commit/275d015c680ce9f90cbe285596e50118e472bf24CVE reference, GitHub_M · x_refsource_MISC
- https://github.com/hapifhir/org.hl7.fhir.core/commit/e08982d2b6f6dcd6c670a762d9cf999179fbe4edCVE reference, GitHub_M · x_refsource_MISC
- https://github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.7CVE reference, GitHub_M · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Inefficient Regular Expression Complexity
Inefficient Regular Expression Complexity represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.