Does passing in front of someone performing prayer invalidate their prayer?

Whether in an open or closed area, one should not pass in front of someone performing prayer unless it is absolutely necessary. The Prophet Muhammad (peace be upon him) stated that it is better to wait than to pass in front of someone who is praying. (Bukhari, Salat, 101 [510]; Muslim, Salat, 261 [507]) The person performing prayer should also take precautions to prevent others from passing in front of them, such as standing in a suitable place or placing a barrier (sutrah) in front. The Prophet (peace be upon him) recommended that anyone praying in a place where people or animals might pass in front should place a sutrah (a stick or another object) in front of them. (Muslim, Salat, 241-242 [499]) Neglecting to use a sutrah is considered undesirable (makruh).

Although the person who passes in front of someone praying is held responsible, the prayer of the one being passed in front of is not invalidated. However, in large mosques, it is permissible to pass at a distance from the place where the person performing prayer prostrates. (Kâsânî, Bedâ’i, 1/217)

In congregational prayers, it is sufficient for only the imam to have a sutrah; the others do not need to place one. (Bukhari, Salat, 90 [494-495]) There is no harm in passing beyond the sutrah placed in front of the person performing prayer.

Source: T.C. Diyanet İşleri Başkanlığı, Din İşleri Yüksek Kurulu