CVE-2026-9558
CRITICAL
NVD
CVSS Score
9.9
Severity
CRITICAL
Published
May 29, 2026
Vendor
unknown
Description
A Server-Side Template Injection (SSTI) vulnerability exists in Mautic's theme engine. The platform renders uploaded Twig templates without a sandbox or strict function restrictions. Authenticated users with permissions to create or upload themes can abuse this to execute arbitrary code on the hosting server (Remote Code Execution) or access restricted system files and configuration settings.