CVE-2025-15503 is a vulnerability identified in the Sangfor Operation and Maintenance Management System (O&M System) versions 3.0.0 through 3.0.8. The flaw resides in an unspecified function within the JSP file located at /fort/trust/version/common/common.jsp, where manipulation of the File argument allows attackers to perform unrestricted file uploads. This vulnerability is remotely exploitable without requiring any authentication or user interaction, significantly lowering the barrier for attackers. The unrestricted upload capability can be leveraged to place malicious files on the server, which may include web shells or other payloads enabling remote code execution, privilege escalation, or persistent access. The CVSS 4.0 base score is 6.9, reflecting medium severity, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The impact on confidentiality, integrity, and availability is low to limited but can escalate depending on the payload deployed. The vendor has not issued any patches or advisories and has not responded to disclosure attempts, increasing the risk exposure. Although no known exploits in the wild have been reported yet, the public release of exploit code raises the likelihood of imminent attacks. The vulnerability affects a management system often used in operational environments, making it a critical target for attackers aiming to disrupt or infiltrate enterprise IT operations.

For European organizations, the unrestricted upload vulnerability in Sangfor's O&M System poses significant risks. Successful exploitation can lead to unauthorized system access, data theft, or disruption of critical maintenance operations. This is particularly concerning for sectors relying on Sangfor products for infrastructure management, such as telecommunications, energy, and large enterprises. Compromise could result in downtime, loss of sensitive operational data, and potential lateral movement within networks. Given the lack of vendor response and patches, organizations face prolonged exposure. The public availability of exploit code increases the risk of opportunistic attacks, including ransomware deployment or espionage. The impact extends beyond individual organizations to potentially affect supply chains and critical infrastructure stability in Europe. Additionally, regulatory compliance risks arise if breaches lead to personal data exposure under GDPR. The medium severity rating may underestimate the real-world impact if attackers leverage the vulnerability for advanced persistent threats or widespread disruption.

Since no official patches or vendor advisories are available, European organizations should implement immediate compensating controls. First, restrict network access to the Sangfor O&M System, limiting it to trusted management networks and blocking internet exposure. Deploy web application firewalls (WAFs) or intrusion prevention systems (IPS) with custom rules to detect and block suspicious file upload attempts targeting the vulnerable JSP endpoint. Conduct thorough logging and monitoring of file upload activities and anomalous behavior on affected servers. Isolate the Sangfor system from critical production environments to contain potential breaches. Consider deploying endpoint detection and response (EDR) solutions to identify post-exploitation activities. Organizations should also review and harden file system permissions to limit the impact of malicious uploads. Engage with Sangfor support channels persistently for updates and patches. Finally, prepare incident response plans specific to this vulnerability, including rapid containment and forensic analysis procedures.