telnet-bsd: Multiple buffer overflows

Background

telnet-bsd provides a command line telnet client which is used for remote login using the telnet protocol.

Description

A buffer overflow has been identified in the env_opt_add() function of telnet-bsd, where a response requiring excessive escaping can cause a heap-based buffer overflow. Another issue has been identified in the slc_add_reply() function, where a large number of SLC commands can overflow a fixed size buffer.

Impact

Successful exploitation would require a vulnerable user to connect to an attacker-controlled host using telnet, potentially executing arbitrary code with the permissions of the telnet user.

Workaround

There is no known workaround at this time.

Resolution

All telnet-bsd users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-misc/telnet-bsd-1.0-r1"