Internet Bug Bounty: OOB write in MDC2_Update() (CVE-2016-6303)

An overflow can occur in MDC2_Update() either if called directly or
through the EVP_DigestUpdate() function using MDC2. If an attacker
is able to supply very large amounts of input data after a previous
call to EVP_EncryptUpdate() with a partial block then a length check
can overflow resulting in a heap corruption.

The amount of data needed is comparable to SIZE_MAX which is impractical
on most platforms.

refer:
https://www.openssl.org/news/secadv/20160922.txt