Graphviz is an open source graph visualization software.
Roee Hay reported a stack-based buffer overflow in the push_subg() function in parser.y when processing a DOT file with a large number of Agraph_t elements.
A remote attacker could entice a user or automated system to open a specially crafted DOT file in an application using Graphviz, possibly leading to the execution of arbitrary code.
There is no known workaround at this time.
All Graphviz users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=media-gfx/graphviz-2.20.3"