CVE-2026-2976: Fastapi-admin Information Disclosure Flaw

CVE-2026-2976 Overview

A path traversal vulnerability has been identified in FastApiAdmin versions up to 2.2.0. This security weakness affects the download_controller function within the file /backend/app/api/v1/module_common/file/controller.py of the Download Endpoint component. By manipulating the file_path argument, an attacker can exploit this vulnerability to achieve unauthorized information disclosure. The vulnerability is remotely exploitable, and exploit details have been made publicly available, increasing the risk of active exploitation.

Critical Impact

Remote attackers with low privileges can exploit the path traversal vulnerability in the Download Endpoint to access sensitive files and disclose confidential information from affected FastApiAdmin installations.

Affected Products

• FastApiAdmin fastapi-admin version 2.0
• FastApiAdmin fastapi-admin version 2.1
• FastApiAdmin fastapi-admin version 2.2.0

Discovery Timeline

• 2026-02-23 - CVE CVE-2026-2976 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2026-2976

Vulnerability Analysis

This vulnerability represents a classic path traversal (CWE-200: Information Exposure) issue in the FastApiAdmin web application framework. The affected download_controller function fails to properly sanitize the file_path parameter before processing file download requests. This insufficient input validation allows attackers to craft malicious requests containing directory traversal sequences (such as ../) to escape the intended directory structure and access files outside the designated download path.

The vulnerability is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) and CWE-434 (Unrestricted Upload of File with Dangerous Type), indicating that the download endpoint lacks proper access controls and path validation mechanisms. Attackers exploiting this flaw can potentially read sensitive configuration files, application source code, database credentials, or other confidential data stored on the server.

Root Cause

The root cause of this vulnerability lies in the improper input validation within the download_controller function located at /backend/app/api/v1/module_common/file/controller.py. The function accepts a user-controlled file_path parameter without adequately sanitizing or validating it against path traversal attempts. The code fails to:

1. Normalize the file path to remove traversal sequences
2. Verify that the resolved path remains within the allowed download directory
3. Implement proper access control checks before serving files

This allows attackers to supply path traversal payloads that bypass intended directory restrictions and access arbitrary files on the system that the web application has read permissions for.

Attack Vector

The attack can be initiated remotely over the network by authenticated users with low-level privileges. An attacker would send a crafted HTTP request to the Download Endpoint with a manipulated file_path parameter containing directory traversal sequences. For example, by injecting sequences like ../../../etc/passwd into the file_path parameter, the attacker could traverse out of the intended download directory and retrieve sensitive system files.

The vulnerability manifests in the download endpoint's file handling mechanism. Attackers can exploit the insufficient path validation by constructing requests with traversal sequences in the file_path parameter. For detailed technical analysis, see the GitHub Vulnerability Repository.

Detection Methods for CVE-2026-2976

Indicators of Compromise

• HTTP requests to Download Endpoint URLs containing path traversal patterns such as ../, ..%2f, %2e%2e/, or similar encoded variants
• Unusual file access patterns in application logs showing attempts to access files outside the designated download directory
• Web server logs containing requests with file_path parameters referencing system configuration files like /etc/passwd or Windows system files

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block path traversal patterns in request parameters
• Monitor application logs for anomalous file download requests targeting sensitive directories or system files
• Configure intrusion detection systems (IDS) to alert on HTTP requests containing directory traversal sequences to FastApiAdmin endpoints

Monitoring Recommendations

• Enable verbose logging on the FastApiAdmin Download Endpoint to capture all file access attempts with full request parameters
• Set up automated alerting for any file access attempts outside the designated download directory boundaries
• Regularly audit access logs for patterns indicative of reconnaissance or exploitation attempts against file download functionality

How to Mitigate CVE-2026-2976

Immediate Actions Required

• Restrict access to the Download Endpoint to only trusted, authenticated users with a legitimate business need
• Implement additional input validation at the network perimeter using a WAF to filter path traversal patterns
• Audit and remove unnecessary read permissions from the web application service account to limit the scope of potential information disclosure
• Consider temporarily disabling the Download Endpoint if it is not critical to operations until a patch is applied

Patch Information

At the time of publication, no official vendor patch has been released for this vulnerability. Organizations should monitor the FastApiAdmin project for security updates. For the latest information regarding patches and advisories, refer to the VulDB Entry #347360 and the GitHub Vulnerability Repository.

Workarounds

• Implement custom input validation middleware to sanitize the file_path parameter before it reaches the download_controller function
• Use a reverse proxy to filter and reject requests containing path traversal sequences targeting the Download Endpoint
• Restrict the web application's file system access using chroot or container isolation to limit the scope of accessible files

# Example: Input validation middleware configuration (conceptual)
# Add path normalization and validation before file access
# Ensure resolved paths remain within ALLOWED_DOWNLOAD_DIR
# Reject requests containing traversal sequences: ../, %2e%2e/, etc.