To learn more about what information is available to someone observing the different parts of a Tor circuit, see the interactive graphics at <a href="https://support.torproject.org/https/https-1/">Tor FAQ: Can exit nodes eavesdrop on communications?</a>.
Tor exit nodes have been used in the past to collect sensitive information from unencrypted connections. Malicious exit nodes are regularly identified and removed from the Tor network. For an example, see <a href="https://arstechnica.com/information-technology/2007/09/security-expert-used-tor-to-collect-government-e-mail-passwords/">Ars Technica: Security expert used Tor to collect government e-mail passwords</a>.