A security issue is a type of bug that can affect the security of WordPress installations.
Specifically, it is a report of a bug that you have found in the WordPress core code, and that you have determined can be used to gain some level of access to a site running WordPress that you should not have.
Your site being “hacked” is not a security issue. The security issue will involve knowing how the attacker got in and hacked the site. If you have details on the attack, then email us.
You forgetting your password or losing access to your site is not a security issue. If you lost access through a bug in the WordPress code, then that might be a security issue.
Generally, security issues are complex problems. If you are wanting to report a security issue, then that’s great! You’re in the right place. However, be sure that what you’re reporting is actually a security issue. The experts that you are reporting it to are very busy, and don’t usually respond to non-security issues.
In other words, the security mailing addresses are NOT for support. Don’t send general problems to them.