Heads Up :
The post you are writing will appear in a public forum. Please ensure all content is appropriate for public consumption. Review the employee guidelines for the community here.
Seems like Cisco has now provided some details here:https://www.cisco.com/c/en/us/td/docs/security/vpn_client/anyconnect/anyconnect49/upgrade/AnyConnect_macOS_BigSur_Advisory.html