The answer is due to the Stevens et. al's work ;

 - [Chosen-prefix collisions for MD5 and applications][1],  2012.

They showed that, with an approximately $2^{39}$ calls to the MD5 compression function, it is possible, for any chosen $m_1$ and $m_2$, to **construct** $s_1$ and $s_2$ such that $$\text{MD5} (m_1\mathbin\|s_1) = \text{MD5} (m_2\mathbin\|s_2)$$

They also gave examples for colliding documents, software integrity checking, etc ...


  [1]: https://documents.epfl.ch/users/l/le/lenstra/public/papers/lat.pdf