Google Chrome now blocks access to websites on an additional seven TCP ports to protect against the NAT Slipstreaming 2.0 vulnerability. The vulnerability allows a website to host malicious scripts that send a specially crafted response that bypasses the visitor’s NAT firewall to access any TCP/UDP port on a visitor’s internal network. Chrome will also block HTTP, HTTPS, and FTP access to 69, 137, 161, 1719, 1720, 1723, and 6566 TCP ports. Firefox, Edge, and Safari 14.0.3 have already added mitigations for the vulnerability.
Source: https://www.bleepingcomputer.com/news/security/google-chrome-blocks-7-more-ports-to-stop-nat-slipstreaming-attacks/