Concrete 8.5.7 and below as well as Concrete 9.0 through 9.0.2 allow traversal in /index.php/ccm/system/file/upload which could result in an Arbitrary File Delete exploit. This was remediated by sanitizing /index.php/ccm/system/file/upload to ensure Concrete doesn’t allow traversal and by changing isFullChunkFilePresent to have an early false return when input doesn't match expectations.Concrete CMS Security team ranked this 5.8 with CVSS v3.1 vector AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:H. Credit to Siebene for reporting.

Path traversal in Concrete CMS