FreeXL before 1.0.0i allows remote attackers to cause a denial of service (stack corruption) or possibly execute arbitrary code via a crafted sector in a workbook.
https://www.gaia-gis.it/fossil/freexl/fdiff?v1=2e167b337481dda3&v2=61618ce51a9b0c15&sbs=1
https://security.gentoo.org/glsa/201606-15
http://www.securityfocus.com/bid/73330
http://www.openwall.com/lists/oss-security/2015/03/27/1