I'm not sure law authorize you to publish the code even if you have warned the manufacturer and waited a number of days. The warning could also be taken for blackmail. You'll face serious problems as this is proprietary technology and so you'll violate their copyright.They also can consider your action as intrusive. Further more, if your exploit is used by others for criminal damages, you'll sure be taken for responsible. So :
1. search for a bug bounty programm linked to the company,
2. if no programm found, contact the manufacturer in an anonymous way (there are examples of people accused end sued of trespassing by companies when they were acting in good faith,
3. if no news from them, leave it to others or contact a lawyer in order to insist if you think what you have found can really be harmful.
But never (never) publish the code without having been able to negotiate with the firm and obtain authorization.
1. search for a bug bounty programm linked to the company, 2. if no programm found, contact the manufacturer in an anonymous way (there are examples of people accused end sued of trespassing by companies when they were acting in good faith, 3. if no news from them, leave it to others or contact a lawyer in order to insist if you think what you have found can really be harmful.
But never (never) publish the code without having been able to negotiate with the firm and obtain authorization.