The zero-day telnet security bug that was discovered for Solaris not long ago has now been patched. While considered relatively minor due to the telnet service being a legacy service that by standard practice isn't used much anymore, Sun still created a temporary workaround while a more permanent fix was crafted. Minor or not, people were attempting and succeeding at exploiting the flaw:
The warning comes after Sun confirmed the existence of a worm created to exploit a recently uncovered vulnerability in the Solaris 10 telnet service. The worm was identified by Arbor Networks barely two weeks after the Internet Storm Center uncovered the existence of a possible threat to Sun's operating system.
The telnet service is one the oldest ones ever created for communication, leaving many surprised at an exploit discovered this late in the game.