CVE-2024-27087 is a medium-severity (CVSS 4.6) Cross-site Scripting (XSS) vulnerability in getkirby/cms. O3 Security confirms whether CVE-2024-27087 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Kirby cross-site scripting (XSS) in the link field "Custom" type
Real-World Exposure
getkirby/cmsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Kirby is a content management system. The new link field introduced in Kirby 4 allows several different link types that each validate the entered link to the relevant URL format. It also includes a "Custom" link type for advanced use cases that don't fit any of the pre-defined link formats. As the "Custom" link type is meant to be flexible, it also allows the javascript: URL scheme. In some use cases this can be intended, but it can also be misused by attackers to execute arbitrary JavaScript code when a user or visitor clicks on a link that is generated from the contents of the link field. This vulnerability is patched in 4.1.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | getkirby/cms | ≥ 4.0.0&&< 4.1.1 | 4.1.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for getkirby/cms. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update getkirby/cms to 4.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-27087 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2024-27087 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2024-27087. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-27087 in your dependencies?
O3 detects CVE-2024-27087 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.