CVE-2026-34566: CI4-CMS-ERP CI4MS

Critical severity, CVSS 9.0. EPSS: 0.4% chance of exploitation in the next 30 days.

CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with RBAC authorization and theme support. Prior to version 0.31.0.0, the application fails to properly sanitize user-controlled input within the Page Management functionality when creating or editing pages. Multiple input fields accept attacker-controlled JavaScript payloads that are stored server-side. These stored values are later rendered without proper output encoding across administrative page lists and public-facing page views, leading to stored DOM-based cross-site scripting (XSS). This issue has been patched in version 0.31.0.0.

Affected products

• CI4-CMS-ERP CI4MS: before 0.31.0.0 (fixed in 0.31.0.0)

Published 2026-04-01. Last modified 2026-06-17.