Fetch-url-file-3a-2f-2f-2f

Or using fetch in Node.js with node-fetch (but node-fetch does not support file:// natively — you’d use fs instead).

If you identify where the string is generated, ensure you are not double-encoding or mis-encoding URLs. Use standard libraries:

In web development, certain characters like colons and slashes are reserved. When they appear in data that isn't part of the main URL structure, they must be encoded. 3A-2F-2F-2F Decoded: :/// fetch-url-file-3A-2F-2F-2F

The file:/// protocol (and its encoded form file-3A-2F-2F-2F ) is a powerful tool for bridging the gap between web technologies and local file systems. While convenient for development and internal tools, it requires stringent security measures to prevent unauthorized access to sensitive local resources.

The attacker inputs ?page=file-3A-2F-2F-2F-2Fetc-2Fpasswd . Or using fetch in Node

Understanding "fetch-url-file-3A-2F-2F-2F": Decoding the Syntax

Do not allow users to specify relative paths. When they appear in data that isn't part

If possible, only allow file access in specialized, isolated components of your application.