Summary
Kirby vulnerable to self cross-site scripting (self-XSS) in the URL field
TL;DR
This vulnerability affects Kirby sites that use the URL field in any blueprint.
A successful attack commonly requires knowledge of the content structure by the attacker as well as social engineering of a user with access to the Panel. The attack cannot be automated.
The vulnerability is also limited to self-XSS and cannot directly affect other users or visitors of the site.
Introduction
Cross-site scripting (XSS) is a type of vulnerability that allows to execute any kind of JavaScript code inside the 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.
Self cross-site scripting (self-XSS, also called reflected XSS) typically involves a user inadvertently executing malicious code within their own context, often through social engineering techniques. This can occur when a user is tricked into pasting and executing malicious JavaScript code into the browser's developer console, address bar or form fields.
Such vulnerabilities are critical as they allow attackers to gain access to the system or to escalate their privileges if they get access to the Panel session of an admin user. Depending on your site, other JavaScript-powered attacks are possible.
Credits
Thanks to Natwara Archeepsamooth (@PlyNatwara) for responsibly reporting the identified issue.
Impact
The URL field allows users to open the entered link in a new tab by clicking the link icon inside the field. This can be used to quickly verify whether the entered URL is functional and correct.
In affected versions, Kirby copied the entered URL into the link target of that link button without validating or sanitizing the link. This could be abused by attackers with a javascript: URL that would then be executed in the user's context when the link button was clicked with Ctrl+Click/Cmd+Click.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2024-26481 has a CVSS score of 4.2 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.6.6.5, 3.7.5.4, 3.8.4.3, 3.9.8.1, 3.10.0.1, 4.1.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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The problem has been patched in Kirby 3.6.6.5, Kirby 3.7.5.4, Kirby 3.8.4.3, Kirby 3.9.8.1, Kirby 3.10.0.1, and Kirby 4.1.1. Please update to one of these or a later version to fix the vulnerability.
In all of the mentioned releases, we have changed the URL field to only make the link button clickable if the entered URL is valid and safe.
Frequently Asked Questions
- What is CVE-2024-26481? CVE-2024-26481 is a medium-severity cross-site scripting (XSS) vulnerability in getkirby/cms (composer), affecting versions <= 3.6.6.4. It is fixed in 3.6.6.5, 3.7.5.4, 3.8.4.3, 3.9.8.1, 3.10.0.1, 4.1.1. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2024-26481? CVE-2024-26481 has a CVSS score of 4.2 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of getkirby/cms are affected by CVE-2024-26481? getkirby/cms (composer) versions <= 3.6.6.4 is affected.
- Is there a fix for CVE-2024-26481? Yes. CVE-2024-26481 is fixed in 3.6.6.5, 3.7.5.4, 3.8.4.3, 3.9.8.1, 3.10.0.1, 4.1.1. Upgrade to this version or later.
- Is CVE-2024-26481 exploitable, and should I be worried? Whether CVE-2024-26481 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2024-26481 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2024-26481?
- Upgrade
getkirby/cmsto 3.6.6.5 or later - Upgrade
getkirby/cmsto 3.7.5.4 or later - Upgrade
getkirby/cmsto 3.8.4.3 or later - Upgrade
getkirby/cmsto 3.9.8.1 or later - Upgrade
getkirby/cmsto 3.10.0.1 or later - Upgrade
getkirby/cmsto 4.1.1 or later
- Upgrade