Viewing the situation as of 14 March 2021:
- Remotely exploitable Chromium security vulnerability CVE-2021-21193 is as reported by Google being used in the wild.
- Unfixed in Debian.
- Unfixed in Chromium on Flathub.
- Unfixed in Chromium on Snap Store.
- Fixed in official Google Chrome (non-freedom!) version.
More details in wiki:
Remotely Exploitable Chromium Security Vulnerability CVE-2021-21193 exploited in the wild
Chromium is basically all independent upstream. The relevant ones available for Kicksecure all lag behind with security critical updates.