HAPI FHIR: ReDoS via FHIRPath matches()/replaceMatches() in FHIR Validator HTTP Endpoint
HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.7, the FHIRPathEngine implementation passes user-controlled regular expressions from matches(), matchesFull(), and replaceMatches() to Java regex operations without effective timeouts, allowing catastrophic backtracking and denial of service. This issue is fixed in version 6.9.7.
- Published
- Jul 16, 2026
- Updated
- Jul 18, 2026
- EPSS
- 0.7% · 51th percentile
- CWE
- CWE-1333
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.7%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 7.5
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
hapifhir org.hl7.fhir.core
- < 6.9.7affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Maven | ca.uhn.hapi.fhir:org.hl7.fhir.dstu2 | before 6.9.7 | 6.9.7 |
| Maven | ca.uhn.hapi.fhir:org.hl7.fhir.dstu2016may | before 6.9.7 | 6.9.7 |
| Maven | ca.uhn.hapi.fhir:org.hl7.fhir.dstu3 | before 6.9.7 | 6.9.7 |
| Maven | ca.uhn.hapi.fhir:org.hl7.fhir.r4 | before 6.9.7 | 6.9.7 |
| Maven | ca.uhn.hapi.fhir:org.hl7.fhir.r4b | before 6.9.7 | 6.9.7 |
| Maven | ca.uhn.hapi.fhir:org.hl7.fhir.r5 | before 6.9.7 | 6.9.7 |
| Maven | ca.uhn.hapi.fhir:org.hl7.fhir.validation | before 6.9.7 | 6.9.7 |
| Maven | ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli | before 6.9.7 | 6.9.7 |
Same product
hapifhir: all recordsOther highest-scoring records for the same primary product.
- CVE-2024-52007XXE vulnerability in XSLT parsing in `org.hl7.fhir.core`34Monitor
- CVE-2024-45294`org.hl7.fhir.core` XXE vulnerability in XSLT transforms34Monitor
- CVE-2026-81876HAPI FHIR: SHCParser DEFLATE infinite loop causes denial of service30Monitor
- CVE-2026-81875HAPI FHIR: SHCParser unbounded DEFLATE decompression causes denial of service30Monitor
- CVE-2026-62296HAPI FHIR: XHTML narrative parser unbounded recursion causes StackOverflow denial of service30Monitor
- CVE-2026-62295HAPI FHIR: JSON utility parser unbounded recursion causes StackOverflow denial of service30Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| hapifhir org.hl7.fhir.core | 6.9.7 · description | Vendor (CNA) |
| Maven:ca.uhn.hapi.fhir:org.hl7.fhir.dstu2 | 6.9.7 | Package registry (OSV) |
| Maven:ca.uhn.hapi.fhir:org.hl7.fhir.dstu2016may | 6.9.7 | Package registry (OSV) |
| Maven:ca.uhn.hapi.fhir:org.hl7.fhir.dstu3 | 6.9.7 | Package registry (OSV) |
| Maven:ca.uhn.hapi.fhir:org.hl7.fhir.r4 | 6.9.7 | Package registry (OSV) |
| Maven:ca.uhn.hapi.fhir:org.hl7.fhir.r4b | 6.9.7 | Package registry (OSV) |
| Maven:ca.uhn.hapi.fhir:org.hl7.fhir.r5 | 6.9.7 | Package registry (OSV) |
| Maven:ca.uhn.hapi.fhir:org.hl7.fhir.validation | 6.9.7 | Package registry (OSV) |
| Maven:ca.uhn.hapi.fhir:org.hl7.fhir.validation.cli | 6.9.7 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-1333 · Inefficient Regular Expression ComplexityCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
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Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/hapifhir/org.hl7.fhir.core/commit/275d015c680ce9f90cbe285596e50118e472bf24
- github.com/hapifhir/org.hl7.fhir.core/commit/e08982d2b6f6dcd6c670a762d9cf999179fbe4ed
- github.com/hapifhir/org.hl7.fhir.core/pull/2403
- github.com/hapifhir/org.hl7.fhir.core/pull/2463
- github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.7
- github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-3653-68v6-rq57
Vendor advisories and official records. Exploit/PoC links are deliberately left out.