Is this a security problem? Depends on who you ask - but I'm willing to bet it would fall into the "accepted risk" category for the Facebook security team if they had to evaluate this.
The reality is that phone number lookup services are available all over the web which provide even more information (first+last name, address, zip code, social media profile links, etc etc etc) for free (https://www.bestfreephonelookup.com/phone-number/ as an example) - these services get their info from data aggregators and usually - your carrier! I don't see how Facebook exposing (in _limited_, very specific circumstances) the first name of a persons phone number being a security issue.
All the people in this thread screaming GDPR violation don't understand that if someone decides to stop using Facebook and delete their account, this method to lookup someone will not work. Sidenote: If you're really paranoid about having your phone number expose your real name when you're using any type of service online, just sign up for a Google Voice (voice.google.com) account and link it to your cell phone - I use this whenever I sign up for anything online and it saves me a ton of spam and scam calls.
EDIT: Facebook removed the ability to use the in-app search box in Facebook to find people based on just a phone number, this has been removed for at least 2 years.
The reality is that phone number lookup services are available all over the web which provide even more information (first+last name, address, zip code, social media profile links, etc etc etc) for free (https://www.bestfreephonelookup.com/phone-number/ as an example) - these services get their info from data aggregators and usually - your carrier! I don't see how Facebook exposing (in _limited_, very specific circumstances) the first name of a persons phone number being a security issue.
All the people in this thread screaming GDPR violation don't understand that if someone decides to stop using Facebook and delete their account, this method to lookup someone will not work. Sidenote: If you're really paranoid about having your phone number expose your real name when you're using any type of service online, just sign up for a Google Voice (voice.google.com) account and link it to your cell phone - I use this whenever I sign up for anything online and it saves me a ton of spam and scam calls.
EDIT: Facebook removed the ability to use the in-app search box in Facebook to find people based on just a phone number, this has been removed for at least 2 years.