I'm not a lawyer, and, if you're concerned about this, I definitely recommend that you consult with one —open-source licensing, IP, and copyright law is highly nuanced, and something that can't really be addressed in a blanket manner that applies to all scenarios.
Some resources of possible interest:
https://legalict.com/2016/01/07/what-is-the-license-status-of-stackoverflow-code-snippets/