CVE-2026-45368: Kirby CMS stored XSS via dangerous URL schemes in KirbyTags

CVE-2026-45368 · Severity: high · CVSS 4 · Published 2026-07-16

Kirby CMS, a popular content management system, contains a security flaw that allows users with content editing permissions to inject malicious scripts into website links. If a site visitor or administrator clicks on one of these manipulated links, the attacker's script could execute in their browser, potentially leading to account takeover or unauthorized actions. This issue specifically affects sites where content is authored by users who are not fully trusted.

Technologies: Kirby, getkirby/cms (Packagist). Vendors: Kirby, Packagist.

Quick answers

Is CVE-2026-45368 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-45368 being exploited in the wild.
How severe is CVE-2026-45368?
High severity, with a CVSS score of 4, published 16 July 2026.
Which products and versions are affected?
Kirby < 4.9.1, >= 5.0.0, < 5.4.1, <= 4.9.0, >= 5.0.0, <= 5.4.0; getkirby/cms (Packagist) ECOSYSTEM:introduced=0,fixed=4.9.1.
Is there a fix for CVE-2026-45368?
Yes. getkirby/cms (Packagist): upgrade to 4.9.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-45368 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-45368?
Check whether you run Kirby or getkirby/cms (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • getkirby/cms (Packagist): upgrade to 4.9.1 or later
    composer require getkirby/cms:^4.9.1

Technical details

A stored cross-site scripting (XSS) vulnerability exists in Kirby CMS due to insufficient filtering of dangerous URI schemes in the underlying URL methods used by KirbyTags and image blocks. While basic 'javascript:' schemes were previously blocked, attackers can bypass these filters using obfuscated formats like 'javascript://x%0A…' or other dangerous schemes such as 'vbscript:', 'data:', and 'jar:'. The vulnerability affects the (link: …) KirbyTag, the link parameter of the (image: …) KirbyTag, the image block link field, and the HTML importer for blocks. An attacker with 'update' permissions to textarea or blocks fields can inject these malicious URLs, which are then rendered as <a> tags in the site frontend. Exploitation requires a victim to click the malicious link. The issue is fixed in versions 4.9.1 and 5.4.1 by implementing a new dangerous scheme detection method.

Affected products

  • getkirby Kirby CMS < 4.9.1, >= 5.0.0, < 5.4.1

Identifiers

  • CVE-2026-45368
  • GHSA-qvjf-922g-pj44

Timeline

  • 2026-05-19: patched: Versions 4.9.1 and 5.4.1 released
  • 2026-05-19: advisory: GitHub Security Advisory GHSA-qvjf-922g-pj44 published
  • 2026-07-16: disclosed: CVE-2026-45368 published to NVD

References

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