Summary
Kirby vulnerable to path traversal in the router for PHP's built-in server
TL;DR
This vulnerability affects all Kirby setups that use PHP's built-in server. Such setups are commonly only used during local development.
Sites that use other server software (such as Apache, nginx or Caddy) are not affected.
Introduction
For use with PHP's built-in web server, Kirby provides a router.php file. The router delegates requests to static files to PHP so that assets and other static files in the document root can be accessed by the browser.
This logic was vulnerable against path traversal attacks. By using special elements such as .. and / separators, attackers can escape outside of the restricted location to access files or directories that are elsewhere on the system. One of the most common special elements is the ../ sequence, which in most modern operating systems is interpreted as the parent directory of the current location.
Impact
The missing path traversal check allowed attackers to navigate all files on the server that were accessible to the PHP process, including files outside of the Kirby installation.
The vulnerable implementation delegated all existing files to PHP, including existing files outside of the document root. This leads to a different response that allows attackers to determine whether the requested file exists.
Because Kirby's router only delegates such requests to PHP and does not load or execute them, contents of the files were not exposed as PHP treats requests to files outside of the document root as invalid.
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
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 3.9.8.3, Kirby 3.10.1.2 and Kirby 4.7.1. Please update to one of these or a later version to fix the vulnerability.
In all of the mentioned releases, we have updated the router to check if existing static files are within the document root. Requests to files outside the document root are treated as page requests of the error page and will no longer allow to determine whether the file exists or not.
Frequently Asked Questions
- What is CVE-2025-30207? CVE-2025-30207 is a low-severity path traversal vulnerability in getkirby/cms (composer), affecting versions < 3.9.8.3. It is fixed in 3.9.8.3, 3.10.1.2, 4.7.1. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- Which versions of getkirby/cms are affected by CVE-2025-30207? getkirby/cms (composer) versions < 3.9.8.3 is affected.
- Is there a fix for CVE-2025-30207? Yes. CVE-2025-30207 is fixed in 3.9.8.3, 3.10.1.2, 4.7.1. Upgrade to this version or later.
- Is CVE-2025-30207 exploitable, and should I be worried? Whether CVE-2025-30207 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-2025-30207 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-2025-30207?
- Upgrade
getkirby/cmsto 3.9.8.3 or later - Upgrade
getkirby/cmsto 3.10.1.2 or later - Upgrade
getkirby/cmsto 4.7.1 or later
- Upgrade