Kirby

Kirby CMS versions prior to 4.9.4 and between 5.0.0-alpha.1 and 5.4.3 are vulnerable to a self-cross-site scripting (self-XSS) flaw, CVE-2026-49276, in the writer field, allowing an attacker to inject malicious JavaScript as the target of a link or email link which, if clicked by an authenticated user before saving, will execute in their browser context, potentially making API requests with their permissions, while Panel plugins using the `<k-writer>` component may be vulnerable to stored XSS if they don't sanitize HTML.

An authenticated user can exploit CVE-2026-54005, a high-severity missing authorization vulnerability in Kirby CMS versions <= 4.9.3 and from 5.0.0-alpha.1 to <= 5.4.3, via the `/api/site/find` REST API route to bypass `pages.access` permissions and retrieve sensitive content and metadata from unauthorized pages.

A critical external initialization vulnerability (CVE-2026-54003) in Kirby CMS allows unauthenticated attackers to create an initial admin account on sites running behind a reverse proxy, specifically when the proxy utilizes `Forwarded: for=...`, `X-Client-IP`, or `X-Real-IP` headers, bypassing Kirby's `isLocal` check and enabling remote Panel installation with full administrative access.

A server-side template injection (SSTI) vulnerability exists in Kirby CMS within the option rendering feature due to double template resolution in option fields (checkboxes, color, multiselect, select, radio, tags, or toggles) when using options from a query or API with untrusted values, potentially allowing attackers to inject malicious queries.