Input validation error in FHIR - CVE-2026-49485
Published: July 14, 2026
Vulnerability identifier: #VU137475
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-49485
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper input validation in FHIRPathEngine when evaluating user-supplied FHIRPath regular expressions through matches(), matchesFull(), and replaceMatches(). A remote attacker can send a crafted resource containing a malicious regex pattern to cause a denial of service.
The issue is caused by catastrophic backtracking in Java regex processing, and some FHIRPathEngine method calls were not protected by the timeout utility.
Affected software
FHIR
How to mitigate CVE-2026-49485
Install security update from vendor's website.
FHIR - addressed in versions 6.9.4.2, 6.9.9