CVE-2025-8775 is a medium-severity vulnerability affecting the Qiyuesuo Electronic Signature Platform versions up to 4.34. The vulnerability resides in the Scheduled Task Handler component, specifically in the /api/code/upload endpoint's execute function. It allows an attacker to perform an unrestricted file upload by manipulating the 'File' argument. This flaw can be exploited remotely without requiring user interaction or prior authentication, as indicated by the CVSS vector (AV:N/AC:L/AT:N/UI:N/PR:L). The vulnerability's exploitation could enable attackers to upload arbitrary files, potentially leading to remote code execution, unauthorized access, or system compromise depending on the server's configuration and the nature of the uploaded files. The vendor has not responded to disclosure attempts, and no patches or mitigations have been officially released. While no known exploits are currently in the wild, the public disclosure of the exploit increases the risk of exploitation. The CVSS score of 5.3 reflects a medium severity, balancing the ease of exploitation with the limited scope of impact due to the requirement of low privileges (PR:L) and the lack of user interaction or scope change. The vulnerability does not involve confidentiality, integrity, or availability impacts at a high level but poses a significant risk if leveraged for further attacks.

For European organizations using the Qiyuesuo Electronic Signature Platform, this vulnerability could have serious implications. Electronic signature platforms are critical for legal, financial, and administrative processes, and compromise could lead to unauthorized document manipulation, fraud, or leakage of sensitive information. The ability to upload arbitrary files remotely could allow attackers to deploy web shells or malware, leading to broader network compromise. This risk is heightened in sectors with stringent regulatory requirements such as GDPR, where data breaches can result in heavy fines and reputational damage. Additionally, organizations relying on electronic signatures for contract validation or compliance may face operational disruptions or legal challenges if the platform integrity is compromised. Given the vendor's lack of response and absence of patches, European entities must assume a higher risk posture and prepare for potential exploitation attempts.

1. Immediate mitigation should involve restricting access to the /api/code/upload endpoint via network controls such as firewalls or web application firewalls (WAFs) to limit exposure to trusted IP addresses only. 2. Implement strict input validation and file type restrictions at the application or proxy level to prevent unauthorized file types from being uploaded. 3. Monitor logs for unusual upload activity or access patterns to detect potential exploitation attempts early. 4. Employ intrusion detection/prevention systems (IDS/IPS) tuned to detect anomalous file upload behavior. 5. If possible, isolate the affected platform in a segmented network zone to limit lateral movement in case of compromise. 6. Regularly back up critical data and ensure incident response plans include scenarios involving this platform. 7. Engage with the vendor or community to seek updates or unofficial patches and consider alternative solutions if no vendor support is forthcoming. 8. Conduct penetration testing focused on file upload functionalities to identify and remediate similar weaknesses proactively.