The "process-execute" and "process-spawn" procedures in CHICKEN Scheme used fixed-size buffers for holding the arguments and environment variables to use in its execve() call. This would allow user-supplied argument/environment variable lists to trigger a buffer overrun. This affects all releases of CHICKEN up to and including 4.11 (it will be fixed in 4.12 and 5.0, which are not yet released).

The "process-execute" and "process-spawn" procedures did not free memory correctly when the execve() call failed, resulting in a memory leak. This could be abused by an attacker to cause resource exhaustion or a denial of service. This affects all releases of CHICKEN up to and including 4.11 (it will be fixed in 4.12 and 5.0, which are not yet released).