CVE-2017-15288

The compilation daemon in Scala before 2.10.7, 2.11.x before 2.11.12, and 2.12.x before 2.12.4 uses weak permissions for private files in /tmp/scala-devel/${USER:shared}/scalac-compile-server-port, which allows local users to write to arbitrary class files and consequently gain privileges.

Mitigation

1. Use "scala -nocompdaemon MyScript.scala" rather than "scala MyScript.scala" to disable the implicit startup and use of the daemon.

2. Avoid explicitly starting fsc.

This text is borrowed from the upstream security advisory.