InstantCMS is a free and open source content management system. Versions prior to 2.18.2 have a Server-Side Request Forgery (SSRF) vulnerability in the file upload functionality (`system/core/uploader.php` at lines 509-532). When the "upload from URL" feature follows an HTTP redirect, the redirected target URL bypasses the private IP address blacklist check.
This allows authenticated users to scan and access internal network services. Version 2.18.2 contains a fix.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products
instantsoft:icms2