GHSA-rv3r-vqjj-8c76
HIGHCross-site scripting from content entered in the tags and multiselect fields
Blast Radius
getkirby/cms🐘getkirby/cms🐘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 tags and multiselect fields allow to select tags from an autocompleted list. The tags field also allows to enter new tags or edit existing tags. Kirby already handled escaping of the autocompleted tags, but unfortunately the Panel used HTML rendering for new or edited tags as well as for custom tags from the content file.
This allowed attackers with Panel access to store malicious HTML code in a tag. The browser of the victim who visited the modified page in the Panel will then have rendered this malicious HTML code.
It also allowed self-inflicted XSS attacks in the tags field (meaning that malicious code is executed in the browser of the user who entered it). This could be used in social engineering attacks where a victim is convinced by an attacker to enter malicious code into a tags field.
Visitors without Panel access could only use this attack vector if your site allows changing the content of a tags or multiselect field from a frontend form (for example user self-registration or the creation of pages from a contact or other frontend form). If you validate or sanitize the provided form data, you are already protected against such attacks by external visitors.
You are also not affected by these vulnerabilities if your site doesn't have untrustworthy users with Panel access or a way to modify field values from the frontend or if you don't use the tags or multiselect fields.
Patches
The problems have been patched in Kirby 3.5.8.1, Kirby 3.6.6.1 and Kirby 3.7.4. Please update to one of these or a later version to fix the vulnerabilities.
Note: The fixes for these vulnerabilities have the side effect that values in the tags and multiselect fields that come from dynamic options are displayed with double escaping (e.g. the & character is displayed as &). In the fix for Kirby 3.5, every value in the tags field is displayed with double escaping when dynamic options are enabled, while dynamic options themselves are displayed with triple escaping. We will fix the double/triple escaping issues with a refactoring of the options fields (tags, multiselect, checkboxes, radio, select and toggles) in Kirby 3.8.
Workarounds
We recommend to update to one of the patch releases. If you cannot update immediately, you can work around the issue by disabling the tags and multiselect fields. This can be done by uncommenting these fields from all your blueprints.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | getkirby/cms | ≥ 3.5.7&&< 3.5.8.1 | 3.5.8.1 |
| 🐘Packagist | getkirby/cms | ≥ 3.6.0&&< 3.6.6.1 | 3.6.6.1 |
| 🐘Packagist | getkirby/cms | ≥ 3.7.0&&< 3.7.4 | 3.7.4 |
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 3.5.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rv3r-vqjj-8c76 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 GHSA-rv3r-vqjj-8c76 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 GHSA-rv3r-vqjj-8c76. 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-rv3r-vqjj-8c76 in your dependencies?
O3 detects GHSA-rv3r-vqjj-8c76 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.