gv is a PostScript and PDF viewer for X which provides a user interface for the ghostscript interpreter.
gv contains a buffer overflow vulnerability where an unsafe sscanf() call is used to interpret PDF and PostScript files.
By enticing a user to view a malformed PDF or PostScript file an attacker could execute arbitrary code with the permissions of the user running gv.
There is no known workaround at this time. All users are encouraged to upgrade to the latest available version of gv.
All gv users should upgrade to the latest version:
# emerge sync
# emerge -pv ">=app-text/gv-3.5.8-r4"
# emerge ">=app-text/gv-3.5.8-r4"