CVE-2026-2976 is a medium-severity information disclosure vulnerability identified in FastApiAdmin, an administrative interface framework built on FastAPI. The flaw exists in the download_controller function located in /backend/app/api/v1/module_common/file/controller.py, which handles file download requests. The vulnerability stems from improper validation or sanitization of the file_path parameter, which an attacker can manipulate remotely to access files beyond intended scope. This can lead to unauthorized disclosure of sensitive files or data stored on the server. The vulnerability affects FastApiAdmin versions 2.0, 2.1, and 2.2.0. The CVSS 4.0 vector indicates the attack can be performed remotely (AV:N) with low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and results in limited confidentiality impact (VC:L) without affecting integrity or availability. Although no exploits have been observed in the wild, public exploit code is available, increasing the risk of exploitation. The root cause is insufficient input validation and lack of proper access control enforcement on the download endpoint, which is a common issue in web applications handling file operations. This vulnerability highlights the importance of secure coding practices, especially for file handling functions in web frameworks.

The primary impact of CVE-2026-2976 is unauthorized information disclosure, which can compromise confidentiality by exposing sensitive files or data stored on affected FastApiAdmin servers. Organizations using vulnerable versions may inadvertently leak internal documents, configuration files, or other critical information to remote attackers. Although the vulnerability does not affect integrity or availability, the exposure of sensitive data can lead to further attacks such as social engineering, credential theft, or lateral movement within networks. The ease of remote exploitation without user interaction or elevated privileges increases the risk, especially for publicly accessible administrative interfaces. This can affect organizations across sectors including technology, finance, healthcare, and government that rely on FastApiAdmin for backend management. The medium severity rating reflects the moderate impact and relatively straightforward exploitation, but the potential for cascading effects elevates the overall risk posture.

To mitigate CVE-2026-2976, organizations should prioritize upgrading FastApiAdmin to a patched version once it is released by the vendor. In the interim, implement strict input validation on the file_path parameter to ensure it does not allow directory traversal or access to unauthorized files. Employ allowlisting of permissible file paths or directories to restrict downloads to safe locations only. Enforce robust access controls and authentication on the download endpoint to limit access to authorized users. Consider implementing web application firewalls (WAFs) with rules to detect and block suspicious file path manipulations. Regularly audit and monitor logs for unusual file access patterns indicative of exploitation attempts. Additionally, conduct code reviews and security testing focused on file handling functions to identify and remediate similar issues proactively. Educate developers on secure coding practices related to file operations and parameter sanitization to prevent recurrence.