CVE-2026-62295
HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.11, the JSON utility parser in org.hl7.fhir.utilities.json.parser.JsonParser enforces no maximum nesting depth for arrays or objects. As a result, a small but deeply nested, syntactically valid FHIR JSON document can trigger unbounded readArray() or readObject() recursion, raising a StackOverflowError before structural validation runs. An attacker who can submit JSON resources for validation can thus crash the request thread, and services that do not isolate StackOverflowError safely may experience worker loss or process instability — a denial-of-service condition. This issue is fixed in version 6.9.11.
No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.
Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.
Severity metrics
CVSS 3.1 : 7.5 HIGH
Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.