MaxKB is an open-source AI assistant for enterprise. Prior to 2.8.1, MaxKB v2.8.0 and prior are vulnerable to a server-side request forgery (SSRF) bypass in the OSS file service URL fetch (chat/api/oss/get_url) endpoint. The vulnerability exists due to inconsistent URL parsing between the urlparse validation function and the requests HTTP client, allowing attackers to access internal network services. This vulnerability is fixed in 2.8.1.