FastGPT versions prior to 4.15.2 contain a Server-Side Request Forgery vulnerability that allows authenticated attackers to bypass security controls and access sensitive internal resources.

This is a time-of-check to time-of-use (TOCTOU) flaw in the Axios request interceptor that facilitates Server-Side Request Forgery (CWE-918). An authenticated attacker can exploit the DNS rebinding window to bypass hostname validation, allowing the application to reach private or internal network services that would otherwise be restricted.

The ability to perform SSRF poses a significant risk to internal infrastructure by allowing attackers to interact with services hidden behind a firewall. With a CVSS score of 6.3, this vulnerability could lead to the unauthorized exposure of sensitive metadata, internal configuration data, or private API endpoints, potentially resulting in full system compromise if those services lack secondary authentication.

Immediate Action: Upgrade labring FastGPT to version 4.15.2 or later to resolve the DNS rebinding flaw in the request interceptor.

Proactive Monitoring: Review server logs for anomalous outbound HTTP requests or attempts to access internal loopback addresses and private IP ranges from the FastGPT service.

Compensating Controls: Implement strict egress filtering on the host machine to prevent the application from communicating with unauthorized internal or metadata services.

Public Exploit Available: Unknown

Given the potential for unauthorized access to internal network resources, organizations utilizing FastGPT should prioritize applying the patch to version 4.15.2 immediately. Administrators should verify their current deployment version and ensure that the update is applied in all environments to prevent potential exploitation of this SSRF vector.