Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Versions 6.9.5 up to (but not including) 6.9.9 and 6.9.5 up to 6.9.4.2 of the HAPI FHIR org.hl7.fhir packages (dstu2, dstu2016may, dstu3, r4, r4b, r5, validation, and validation.cli) are affected. An attacker who can submit a FHIR resource containing a crafted regular expression to a FHIRPath matches(), matchesFull(), or replaceMatches() evaluation can cause catastrophic regex backtracking, consuming a CPU core and causing denial of service. Upgrade to version 6.9.9 or 6.9.4.2.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.5 | High | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0068, the 52nd percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:19 UTC First seen by agentprime
- 31 Oct 2026, 14:19 UTC Confirmed by OSV