LessTif is a clone of OSF/Motif, which is the standard user interface toolkit available on Unix and Linux.
Chris Evans has discovered various integer and stack overflows in libXpm, which is shipped as a part of the X Window System. LessTif, an application that includes this library, is susceptible to the same issues.
A carefully-crafted XPM file could crash applications that are linked against libXpm, such as LessTif, potentially allowing the execution of arbitrary code with the privileges of the user running the application.
There is no known workaround at this time.
All LessTif users should upgrade to the latest version:
# emerge sync
# emerge -pv ">=x11-libs/lesstif-0.93.97"
# emerge ">=x11-libs/lesstif-0.93.97"