GNU gv is a viewer for PostScript and PDF documents.
GNU gv does not properly boundary check user-supplied data before copying it into process buffers.
An attacker could entice a user to open a specially crafted document with GNU gv and execute arbitrary code with the rights of the user on the system.
There is no known workaround at this time.
All gv users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-text/gv-3.6.2-r1"