October CMS safe mode bypass using Twig sandbox escape
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.
Source excerpt · OSVAffected packages
Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.
| Affected range | Recorded fix |
|---|---|
| From 3.0.0 before 3.4.15Ecosystem versions | 3.4.15 |
Version evidence: OSV · GHSA-p8q3-h652-65vx
View original version evidence (0 explicit versions)
Original source description
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:
For more information
If you have any questions or comments about this advisory:
- Email us at hello@octobercms.com