GHSA-qc86-q28f-ggww
Craft CMS has potential authenticated Remote Code Execution via Twig SSTI
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Packagist | craftcms/cms | >= 5.0.0-RC1, < 5.9.0-beta.1 | 5.9.0-beta.1 |
| Packagist | craftcms/cms | >= 4.0.0-RC1, < 4.17.0-beta.1 | 4.17.0-beta.1 |
Details
As written in the advisory (Markdown source, shown as plain text).
For this to work, the attacker must have administrator access to the Craft Control Panel, and [allowAdminChanges](https://craftcms.com/docs/5.x/reference/config/general.html#allowadminchanges) must be enabled, which is against Craft CMS' recommendations for any non-dev environment.
https://craftcms.com/knowledge-base/securing-craft#set-allowAdminChanges-to-false-in-production
Alternatively, they can have a non-administrator account with `allowAdminChanges` disabled, but they must have access to the System Messages utility.
It is possible to craft a malicious payload using the Twig `map` filter in text fields that accept Twig input under Settings in the Craft control panel or using the System Messages utility, which could lead to a RCE.
Users should update to the patched versions (5.8.22 and 4.16.18) to mitigate the issue.
References:
https://github.com/craftcms/cms/pull/18208
References
External links from the advisory. They lead to third-party sites.