443
Hundreds of smartphone apps are monitoring users through their microphones
(www.the-independent.com)
This is a most excellent place for technology news and articles.
https://nvd.nist.gov/vuln/detail/CVE-2023-21083
There are probably other exploits around that as well
While these bugs happen, they are fixed very quickly, and wouldn't be used by any marketing agency. Just keep your phone updated.