CVE-2026-2977 is a security vulnerability identified in FastApiAdmin, an administrative interface framework for FastAPI applications, affecting versions 2.0, 2.1, and 2.2.0. The vulnerability resides in the upload_controller function within the Scheduled Task API component, specifically in the file /backend/app/api/v1/module_common/file/controller.py. Due to insufficient validation or restrictions on file uploads, an attacker can remotely upload arbitrary files without requiring authentication or user interaction. This unrestricted upload capability can be exploited to place malicious files on the server, potentially leading to further attacks such as remote code execution, data tampering, or denial of service, depending on how the uploaded files are processed or accessed. The CVSS 4.0 base score is 5.3, indicating a medium severity level, with attack vector being network-based, low attack complexity, no privileges or user interaction required, and limited impacts on confidentiality, integrity, and availability. Although no known exploits are currently active in the wild, the public disclosure increases the risk of exploitation attempts. The vulnerability highlights the need for strict input validation, access controls, and secure handling of file uploads in web applications using FastApiAdmin.

The unrestricted upload vulnerability in FastApiAdmin can have several impacts on organizations worldwide. Attackers could upload malicious files such as web shells, scripts, or malware, potentially leading to unauthorized access, data breaches, or system compromise. Even though the CVSS score indicates medium severity with limited confidentiality, integrity, and availability impacts, the actual impact depends on the deployment context and how uploaded files are handled. For example, if uploaded files are executed or accessible via the web server, attackers could achieve remote code execution or pivot within the network. This could disrupt business operations, lead to data loss or theft, and damage organizational reputation. Organizations relying on FastApiAdmin for administrative interfaces or scheduled task management are particularly at risk. The vulnerability's remote exploitability without authentication increases the attack surface, making it attractive for opportunistic attackers and automated scanning tools. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially after public disclosure.

To mitigate CVE-2026-2977, organizations should first upgrade FastApiAdmin to a version where this vulnerability is patched once available. In the absence of an official patch, implement strict validation on uploaded files, including checking file types, sizes, and content signatures to prevent malicious uploads. Restrict upload functionality to authenticated and authorized users only, applying role-based access controls. Employ network-level protections such as web application firewalls (WAFs) to detect and block suspicious upload attempts. Monitor logs for unusual upload activity and conduct regular security audits of the upload handling code. Isolate the upload directory from execution contexts by configuring the web server to disallow execution of uploaded files. Additionally, consider implementing content security policies and sandboxing techniques to limit the impact of any successful upload. Educate developers and administrators about secure file upload practices and the risks associated with unrestricted uploads. Finally, maintain an incident response plan to quickly address any exploitation attempts.