LessTif is a clone of OSF/Motif, which is a standard user interface toolkit available on Unix and Linux. OpenMotif also provides a free version of the Motif toolkit for open source applications.
Chris Gilbert discovered potentially exploitable buffer overflow cases in libXpm that weren't fixed in previous libXpm security advisories.
A carefully-crafted XPM file could crash applications making use of the OpenMotif or LessTif toolkits, 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 OpenMotif users should upgrade to an unaffected version:
# emerge --sync
# emerge --ask --oneshot --verbose x11-libs/openmotif
All LessTif users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=x11-libs/lesstif-0.94.0-r2"