Executive Summary

[{'type': 'paragraph', 'content': 'CVE-2026-2977 is a security vulnerability in FastApiAdmin versions up to 2.2.0, specifically in the upload_controller function of the Scheduled Task API component. It allows attackers to perform unrestricted file uploads by manipulating the upload mechanism, which relies only on the Content-Type header to determine allowed file extensions without proper validation or path canonicalization.'}, {'type': 'paragraph', 'content': "Attackers can bypass file extension restrictions by disguising malicious files (for example, uploading a Python script as an SVG file), which are then saved directly to the server's upload directory. This can lead to remote code execution when combined with FastApiAdmin's scheduled task APIs."}] [2, 3]

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Impact Analysis

This vulnerability can impact the confidentiality, integrity, and availability of your system. By exploiting it, an attacker can upload arbitrary and potentially dangerous files to your server, which may be executed remotely, leading to unauthorized code execution.

Such exploitation can result in system compromise, data breaches, service disruption, and unauthorized access to sensitive information.

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Compliance Impact

I don't know

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Detection Guidance

[{'type': 'paragraph', 'content': 'This vulnerability can be detected by monitoring for unauthorized or suspicious file uploads to the endpoint /api/v1/common/file/upload, especially uploads that bypass file extension restrictions by manipulating the Content-Type header.'}, {'type': 'paragraph', 'content': 'Detection can involve checking server logs for unusual upload activity, such as files with unexpected extensions or filenames, or uploads by users with the module_common:file:upload permission.'}, {'type': 'paragraph', 'content': 'Suggested commands include searching web server access logs for POST requests to the upload endpoint and inspecting uploaded files for suspicious content or extensions.'}, {'type': 'list_item', 'content': "grep 'POST /api/v1/common/file/upload' /var/log/nginx/access.log"}, {'type': 'list_item', 'content': "find /path/to/upload/directory -type f \\( -name '*.svg' -o -name '*.py' \\) -exec file {} \\; | grep -i 'script'"}, {'type': 'list_item', 'content': 'audit logs review for users with module_common:file:upload permission performing uploads'}] [3]

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Mitigation Strategies

Immediate mitigation steps include implementing strict server-side validation of uploaded files rather than relying on the Content-Type header.

• Validate file magic bytes to confirm actual file type.
• Derive file extensions from the actual content instead of trusting the Content-Type header.
• Normalize and restrict file paths to a safe upload directory that disallows execution permissions.
• Generate randomized, safe filenames for uploads to prevent overwriting or predictable file locations.
• Implement strict allowlists for permitted upload file types.
• Scan uploaded files for dangerous content.
• Apply least-privilege access controls and audit logging for upload and scheduled task APIs to monitor and limit misuse.

Since no official patches or countermeasures are available, replacing the affected FastApiAdmin product with a secure alternative is recommended to avoid exploitation.

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