CVE-2026-49485
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.68%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.68% probability · 51th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-400, CWE-1333
- Source
- security-advisories@github.com
References
- https://github.com/hapifhir/org.hl7.fhir.core/commit/109c88837c032ef399b2eb87ddde86692065cf41
- https://github.com/hapifhir/org.hl7.fhir.core/commit/e08982d2b6f6dcd6c670a762d9cf999179fbe4ed
- https://github.com/hapifhir/org.hl7.fhir.core/pull/2463
- https://github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.4.2
- https://github.com/hapifhir/org.hl7.fhir.core/releases/tag/6.9.9
- https://github.com/hapifhir/org.hl7.fhir.core/security/advisories/GHSA-7cmj-v6x8-frvv
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.