CVE-2026-3683 is a server-side request forgery (SSRF) vulnerability identified in the bufanyun HotGo product up to version 2.0. The flaw resides in the ImageTransferStorage function located in the /server/internal/logic/common/upload.go source file, part of the Endpoint component. SSRF vulnerabilities occur when an attacker can manipulate a server to send crafted requests to unintended locations, potentially accessing internal services or sensitive data not directly exposed to the attacker. In this case, the vulnerability allows remote attackers to exploit the server’s request handling logic without requiring user interaction, but with low privileges (PR:L). The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no user interaction (UI:N), and partial impacts on confidentiality, integrity, and availability (VC:L, VI:L, VA:L). The exploit is publicly available, increasing the risk of exploitation despite no known active attacks in the wild. The vendor was contacted but did not respond or provide a patch, leaving users exposed. This vulnerability could be leveraged to perform internal network scanning, access internal APIs, or exfiltrate data by abusing the server’s trust boundaries. Given the lack of vendor response and patch, organizations must implement compensating controls to mitigate risk.

The SSRF vulnerability in HotGo 2.0 can have several impacts on affected organizations. Attackers could use the vulnerability to access internal network resources that are otherwise inaccessible, potentially leading to information disclosure or further exploitation of internal systems. This could compromise confidentiality by exposing sensitive internal endpoints or data. Integrity and availability impacts are possible if attackers leverage SSRF to interact with internal services in a way that disrupts operations or modifies data. The medium CVSS score reflects that while the vulnerability is exploitable remotely without user interaction, it requires some level of privilege and has limited direct impact on system integrity or availability. However, the potential for lateral movement and reconnaissance within internal networks makes it a significant risk. Organizations relying on HotGo 2.0, especially in sensitive environments, could face data breaches, unauthorized access, or service disruptions if exploited.

Since no official patch or update is available from the vendor, organizations should apply the following specific mitigations: 1) Implement strict network segmentation and firewall rules to limit the server’s ability to make outbound requests to internal or sensitive network segments. 2) Use web application firewalls (WAFs) with custom rules to detect and block suspicious SSRF payloads targeting the ImageTransferStorage endpoint. 3) Conduct thorough input validation and sanitization on any user-supplied URLs or parameters used by the ImageTransferStorage function to prevent malicious request redirection. 4) Monitor logs for unusual outbound requests originating from the HotGo server, especially to internal IP ranges or unexpected external domains. 5) Restrict the privileges of the HotGo service account to minimize the impact of exploitation. 6) Consider deploying network-level egress filtering to prevent unauthorized external requests. 7) If feasible, isolate the HotGo server in a controlled environment with limited network access until a patch is available. 8) Engage in active threat hunting for indicators of compromise related to SSRF exploitation attempts. These measures go beyond generic advice by focusing on network controls, monitoring, and application-level input validation specific to the vulnerable component.