json-c is a JSON implementation in C.
Please review the CVE identifier referenced below for details.
A stack-buffer-overflow exists in the auxiliary sample program json_parse which is located in the function parseit.
There is no known workaround at this time.
All json-c users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-libs/json-c-0.16"