SB2026071459 - Multiple vulnerabilities in FHIR
Published: July 14, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 vulnerabilities.
1) Inefficient regular expression complexity (CVE-ID: CVE-2026-55470)
CWE-ID: CWE-1333 - Inefficient Regular Expression Complexity
CVSSv4: 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]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to inefficient regular expression complexity in FHIRPathEngine.matches() in the DSTU2 module when evaluating user-supplied FHIRPath expressions or resources containing a crafted matches() regular expression. A remote attacker can submit a crafted regular expression that triggers catastrophic backtracking to cause a denial of service.
The issue affects the DSTU2 implementation because the matches() path invokes raw regular expression matching without timeout protection.
2) XML External Entity injection (CVE-ID: CVE-2026-55471)
CWE-ID: CWE-611 - Improper Restriction of XML External Entity Reference ('XXE')
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to disclose sensitive information and perform server-side request forgery.
The vulnerability exists due to improper restriction of xml external entity reference in XsltUtilities.saxonTransform when processing attacker-influenced XML documents or referenced external entities during XSLT transformation. A remote attacker can supply a crafted XML document or influence an external entity reference to disclose sensitive information and perform server-side request forgery.
The issue affects the Saxon-based transform helpers but not the sibling transform helpers that use the hardened XMLUtil factory. Exploitation may occur when the XML source, embedded DTD, or referenced stylesheet is attacker-controlled or can be modified in transit.
Remediation
Install update from vendor's website.