Australia warns of active attacks on TeamCity servers

Australia's Cyber Security Centre warned that attackers are actively exploiting CVE-2026-63077 in TeamCity On-Premises servers. The critical flaw can let an unauthenticated attacker with HTTP(S) access bypass authentication checks and execute operating-system commands. The article says all TeamCity On-Premises versions are affected and advises customers to review their networks, patch vulnerable installations and assess whether their TeamCity interface needs to be internet-exposed. JetBrains previously issued patches and later reported exploitation targeting unpatched servers.