A heap-based buffer overflow flaw was found in the way Perl decoded Unicode strings. An attacker could create a malicious Unicode string that, when decoded by a Perl program, would cause the program to crash or, potentially, execute arbitrary code with the permissions of the user running the program. It was found that the "new" constructor of the Digest module used its argument as part of the string expression passed to the eval function. An attacker could possibly use this flaw to execute arbitrary Perl code with the privileges of a Perl program that uses untrusted input as an argument to the constructor