An issue was discovered in CHICKEN Scheme through 4.12.0. When using a nonstandard CHICKEN-specific extension to allocate an SRFI-4 vector in unmanaged memory, the vector size would be used in unsanitised form as an argument to malloc(). With an unexpected size, the impact may have been a segfault or buffer overflow.
http://www.securityfocus.com/bid/97317
http://lists.gnu.org/archive/html/chicken-announce/2017-03/msg00000.html