Unauthorized access and impersonation can occur in versions 4.6.2.3226 and below of Progress Software's Hybrid Data Pipeline Server on Linux. This vulnerability allows attackers to combine credentials from different sources, potentially leading to client impersonation and unauthorized access.  When OAuth Clients perform an OAuth handshake with the Hybrid Data Pipeline Server, the server accepts client credentials from both HTTP headers and request parameters.

In HDP Server versions below 4.6.2.2978 on Linux, unauthorized access could occur via IP spoofing using the X-Forwarded-For header.

Since XFF is a client-controlled header, it could be spoofed, allowing unauthorized access if the spoofed IP matched a whitelisted range.

This vulnerability could be exploited to bypass IP restrictions, though valid user credentials would still be required for resource access.