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 toma la seguridad muy en serio. Abordamos todos los problemas de seguridad que nos presentan e intentamos solucionarlos en un lapso razonable. Muchos anuncios se coordinan con otros distribuidores de software libre y son publicados el mismo día que se publica la vulnerabilidad. Además tenemos un equipo de auditorías de seguridad que revisa el archivo buscando problemas nuevos o sin arreglar.

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

Security hole in I2P 0.9.13
Posted

Other vulnerabilities solved in included applications