GHSA-3f89-869f-5w76 is a medium-severity (CVSS 5.9) Cross-site Scripting (XSS) vulnerability in getkirby/cms. A fix is available for getkirby/cms — see the affected versions and patch details below.
Cross-site scripting from dynamic options in the multiselect field
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-3f89-869f-5w76.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-3f89-869f-5w76 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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
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.
Such vulnerabilities are critical if you might have potential attackers in your group of authenticated Panel users. They can 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.
Impact
The multiselect field allows to select tags from an autocompleted list. Unfortunately, the Panel in Kirby 3.5 used HTML rendering for the raw option value.
This allowed attackers with influence on the options source (e.g. content of sibling pages or an API endpoint) to inject HTML code. If a page in the Panel that uses the manipulated multiselect options was visited by a victim and the victim opened the autocomplete dropdown, the victim's browser will then have rendered this malicious HTML code.
You are not affected by this vulnerability if you don't use the multiselect field or only use it with options that cannot be manipulated by attackers.
Patches
The problem has been patched in Kirby 3.5.8.1. Please update to this or a later version to fix the vulnerability.
Workarounds
We recommend to update to the patch release. If you cannot update immediately, you can work around the issue by disabling the multiselect field. This can be done by uncommenting this field from all your blueprints.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | getkirby/cms | all versions | 3.5.8.1composer require getkirby/cms:^3.5.8.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for getkirby/cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update getkirby/cms to 3.5.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3f89-869f-5w76 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-3f89-869f-5w76 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-3f89-869f-5w76. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3f89-869f-5w76 in your dependencies?
O3 Security finds GHSA-3f89-869f-5w76 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.