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.

A high-severity cross-site scripting (XSS) vulnerability, tracked as CVE-2026-54002, exists in Kirby CMS versions prior to 4.9.4 and between 5.0.0-alpha.1 and 5.4.3, allowing authenticated Panel users to inject malicious markup into `writer` or `list` fields or via `Sane` API-dependent custom code, leading to stored XSS and potential privilege escalation.

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.

Kirby CMS versions 5.3.0 through 5.4.0 are vulnerable to pre-authentication path traversal, allowing an attacker to include arbitrary PHP files with the filename `index.php`, potentially leading to sensitive information disclosure or malicious actions due to insufficient validation of the provided user ID during user lookup.

Kirby CMS versions before 4.9.0 and between 5.0.0 and 5.3.3 contain a missing authorization vulnerability, allowing authenticated Panel users to access site model, user, and role information without proper permission checks, potentially leading to unauthorized information disclosure.