An issue was discovered in lib\cdt\dttree.c in libcdt.a in graphviz 2.40.1. Stack consumption occurs because of recursive agclose calls in lib\cgraph\graph.c in libcgraph.a, related to agfstsubg in lib\cgraph\subg.c.
https://security.gentoo.org/glsa/202107-04
https://research.loginsoft.com/bugs/stack-buffer-overflow-in-function-agclose-graphviz/