mgetty is a getty replacement for use with data and fax modems.
mgetty can be configured to run an external program to decide whether or
not to answer an incoming call based on Caller ID information. Unpatched
versions of mgetty prior to 1.1.29 would overflow an internal buffer if the
caller name reported by the modem was too long.
Additionally, the faxspool script supplied with versions of mgetty prior to
1.1.29 used a simple permissions scheme to allow or deny fax transmission
privileges. This scheme was easily circumvented because the spooling
directory used for outgoing faxes was world-writable.
