CVE-2026-45368: Kirby CMS vulnerable to cross-site scripting (XSS) from links in KirbyTags and image blocks in the site frontend ### TL;DR This vulnerability affects all Kirby…

high

Kirby CMS vulnerable to cross-site scripting (XSS) from links in KirbyTags and image blocks in the site frontend

### TL;DR

This vulnerability affects all Kirby sites that allow the use of the `(link: …)` KirbyTag, the `link:` parameter of the `(image: …)` KirbyTag, the built-in `image` block with a link or the HTML importer for blocks, when content is authored by users who may not be fully trusted. The attack requires an authenticated Panel user with update permission to any `textarea` or `blocks` field, or write access to content files through another vector (e.g. a frontend form or content sync pipeline). Another attack vector is the use of `Html::a()` or `Html::link()` with untrusted user input.

**This vulnerability is of high severity for affected sites.**

Kirby sites are *not* affected if none of the mentioned KirbyTags or block types are used, or if every user who can edit content is fully trusted. The attack only surfaces in the site frontend (i.e. in its templates). The Panel itself is unaffected and will not execute JavaScript that was injected into the `textarea` or `blocks` field content.

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### Introduction

Cross-site scripting (XSS) is a type of vulnerability that allows to execute any kind of JavaScript code inside the site frontend or Panel session of the same or other users. In the Panel, a harmful script can for example trigger requests to Kirby's API with the permissions of the victim.

In a *stored* XSS attack, the malicious payload is saved into the content data and has the potential to affect other users or site visitors.

Such vulnerabilities are critical if a consuming application might have potential attackers in its group of authenticated Panel users. They can escalate their privileges if they get access to the Panel session of an admin user. Depending on the site, other JavaScript-powered attacks are possible.

A specific class of stored XSS exploits the `javascript:` URI scheme in HTML `` attributes. When a browser processes a clic

Affected

2 ranges

Vendor	Product	Version range	Fixed in
getkirby	cms	>= 0 < 4.9.1	4.9.1
getkirby	cms	>= 5.0.0 < 5.4.1	5.4.1

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