Impact

This is a high-impact, low-complexity attack vector. Users running Craft installations before 4.4.15 are encouraged to update to at least that version to mitigate the issue.

Mitigations

This has been fixed in Craft 4.4.15. You should ensure you’re running at least that version. Refresh your security key in case it has already been captured. You can do that by running the php craft setup/security-key command and copying the updated CRAFTSECURITYKEY environment variable to all production environments. If you have any other private keys stored as environment variables (e.g., S3 or Stripe), refresh those as well. Out of an abundance of caution, you may want to force all your users to reset their passwords in case your database was compromised. You can do that by running php craft resave/users --set passwordResetRequired --to "fn() => true".

References

https://github.com/craftcms/cms/commit/c0a37e15cc925c473e60e27fe64054993b867ac1#diff-47dd43d86f85161944dfcce2e41d31955c4184672d9bd9d82b948c6b01b86476

https://github.com/craftcms/cms/commit/7359d18d46389ffac86c2af1e0cd59e37c298857

https://github.com/craftcms/cms/commit/a270b928f3d34ad3bd953b81c304424edd57355e

https://github.com/craftcms/cms/blob/develop/CHANGELOG.md#4415---2023-07-03-critical