Buffer overflow in the "read-string!" procedure in the "extras" unit in CHICKEN stable before 4.8.0.5 and development snapshots before 4.8.3 allows remote attackers to cause a denial of service (memory corruption and application crash) and possibly execute arbitrary code via a "#f" value in the NUM argument.
https://security.gentoo.org/glsa/201612-54
http://www.securityfocus.com/bid/62690
http://secunia.com/advisories/55009
http://lists.nongnu.org/archive/html/chicken-announce/2013-09/msg00001.html
http://lists.nongnu.org/archive/html/chicken-announce/2013-09/msg00000.html
http://lists.gnu.org/archive/html/chicken-announce/2013-10/msg00000.html