CVE-2026-40100

OVERVIEW CVE-2026-40100 is a Server-Side Request Forgery (SSRF) vulnerability in FastGPT, an AI Agent building platform. The flaw exists in the /api/core/app/mcpTools/runTool endpoint of versions prior to 4.14.10.3, which accepts arbitrary URLs without proper authentication or validation. The vulnerability stems from an insufficient internal IP address check that is disabled by default, allowing attackers to bypass restrictions intended to prevent access to internal network resources. SEVERITY The vulnerability carries a CVSS v3.1 score of 5.3 (Medium) with a network-based attack vector, low complexity, and no authentication requirement. The flaw enables unauthenticated attackers to perform SSRF attacks against internal network resources, potentially leading to unauthorized information disclosure from systems accessible only from the FastGPT server's network position. However, the impact is limited to confidentiality; the vulnerability does not permit integrity or availability attacks. EXPLOITATION STATUS This vulnerability is not currently listed on CISA's Known Exploited Vulnerabilities (KEV) catalog and shows no signs of active exploitation in the wild. The EPSS score of 0.0007 indicates minimal community exploitation activity. The vulnerability remains on an inactive hot list status, suggesting limited public awareness and no readily available public exploit code at this time. Organizations should nonetheless prioritize patching to version 4.14.10.3 to prevent potential future exploitation.