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tx4man · 10-03-2026, 07:44 AM

Hello everyone,

I'm not sure if anyone mentioned this before, but the reader's stock web browser has a vulnerability that allows you to write to /mnt/private directly. So there's no need to bother with serial a COM adapter and disassemble your device.

You just need to run your own web server to download the "hackers_e60q22_ok" authorisation marker from the webserver and take advantage of the Content-Disposition header, and the parent directory ("..") descriptor.

So if a regular download from the webserver without setting up this response header would save your file at /mnt/public/file, in this case we would set the header to /../../private/file to esentially write to /mnt/private:

Content-Disposition: attachment; filename="/mnt/public/randomfolder/../../private/hackers_e60q22_ok"

I've published my findings to https://github.com/x4m4n/bq-cervantes3-offline-unlock, if anyone is interested in following this method. There you'll also find a python3 server preconfigured and ready to go for you to take advantage of this flaw. It's honestly very easy and fast.

10-03-2026, 07:44 AM	#89
tx4man Junior Member Posts: 2 Karma: 52564 Join Date: Oct 2026 Device: BQ Cervantes 3	Hello everyone, I'm not sure if anyone mentioned this before, but the reader's stock web browser has a vulnerability that allows you to write to /mnt/private directly. So there's no need to bother with serial a COM adapter and disassemble your device. You just need to run your own web server to download the "hackers_e60q22_ok" authorisation marker from the webserver and take advantage of the Content-Disposition header, and the parent directory ("..") descriptor. So if a regular download from the webserver without setting up this response header would save your file at /mnt/public/file, in this case we would set the header to /../../private/file to esentially write to /mnt/private: Content-Disposition: attachment; filename="/mnt/public/randomfolder/../../private/hackers_e60q22_ok" I've published my findings to https://github.com/x4m4n/bq-cervantes3-offline-unlock, if anyone is interested in following this method. There you'll also find a python3 server preconfigured and ready to go for you to take advantage of this flaw. It's honestly very easy and fast.