A server-side information disclosure vulnerability was identified in the handling of CSS preprocessor files. Backend users with Editor permissions could craft .less, .sass, or .scss files that leverage the compiler's import functionality to read arbitrary files from the server. This worked even with cms.safe_mode enabled.
cms.safe_mode is enabled (otherwise direct PHP injection is already possible)The vulnerability has been patched in v3.7.14 and v4.1.10. When cms.safe_mode is enabled, .less, .sass, and .scss files can no longer be created, uploaded, or edited across the CMS editor, media manager, and file upload interfaces. All users are encouraged to upgrade to the latest patched version.
If upgrading immediately is not possible:
Set cms.editable_asset_types config to ['css', 'js'] to remove preprocessor file types from the editor
Restrict Editor tool access to fully trusted administrators only
Reported by Chris Alupului
3.7.144.1.10Exploitability
AV:NAC:LPR:HUI:NScope
S:UImpact
C:HI:NA:N4.9/CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N