October is a Content Management System (CMS) and web platform to assist with development workflow. An authenticated backend user with the `editor.cms_pages`, `editor.cms_layouts`, or `editor.cms_partials` permissions who would normally not be permitted to provide PHP code to be executed by the CMS due to `cms.safe_mode` being enabled can write specific Twig code to escape the Twig sandbox and execute arbitrary PHP. This issue has been patched in 3.4.15.

Affected: Packagist: october/system

### Impact

An authenticated backend user with the `editor.cms_pages`, `editor.cms_layouts`, or `editor.cms_partials` permissions who would normally not be permitted to provide PHP code to be executed by the CMS due to `cms.safe_mode` being enabled can write specific Twig code to escape the Twig sandbox and execute arbitrary PHP.

This is not a problem for anyone who trusts their users with those permissions to usually write and manage PHP within the CMS by not having `cms.safe_mode` enabled. Still, it would be a problem for anyone relying on `cms.safe_mode` to ensure that users with those permissions in production do not have access to write and execute arbitrary PHP.

### Patches

This issue has been patched in v3.4.15.

### Workarounds

As a workaround, remove the specified permissions from untrusted users.

### References

Credits to: - [Vasiliy Bodrov](https://github.com/whatev3n)

### For more information If you have any questions or comments about this advisory: * Email us at [hello@octobercms.com](mailto:hello@octobercms.com)