Since Tails is based on Debian, it takes advantage of all the work done by the Debian security team. As quoted from https://www.debian.org/security/:

Debian memperhatikan keamanan dengan sangat serius. Kami menangani seluruh masalah yang membawa perhatian kami dan memastikan mereka di perbaiki dalam jangka waktu yang layak. Banyak penasihat di koordinasikan dengan penjaja perangkat lunak gratis dan diterbitkan di hari yang sama sebuah kerentanan dibuat umum dan kami juga memiliki Tim Pemeriksa Keamanan yang mengulas arsip-arsip untuk mencari bug-bug keamanan yang belum diperbaiki.

Experience has shown that "security through obscurity" does not work. Public disclosure allows for more rapid and better solutions to security problems. In that vein, this page addresses Debian's status with respect to various known security vulnerabilities, which could potentially affect Debian.

Current security vulnerabilities

Fixed security vulnerabilities

Other vulnerabilities solved in included applications