Sangfor Behavior Management System (also referred to as DC Management System in Chinese-language documentation) contains an XML external entity (XXE) injection vulnerability in the /src/sangforindex endpoint. A remote unauthenticated attacker can submit crafted XML data containing external entity definitions, leading to potential disclosure of internal files, server-side request forgery (SSRF), or other impacts depending on parser behavior. The vulnerability is due to improper configuration of the XML parser, which allows resolution of external entities without restriction. This product is now integrated into their IAM (Internet Access Management) platform and an affected version range is undefined. Exploitation evidence was first observed by the Shadowserver Foundation on 2023-09-06 UTC.