In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- Scholars differed concerning stepping over people who are sitting in the mosque on Friday.
2- Some scholars said it is makruh (disliked) while others said it is (haram) forbidden.
Answering your question, the Fatwa Center at Islam Q and A, states:
Stepping Over People Who Are Sitting in the Mosque on Friday
Abu Dawud and Ibn Majah narrated that Abdullah ibn Busr said: A man came and started stepping over the people one Friday when the Messenger of Allah (peace be upon him) was delivering the khutbah, and the Prophet said to him: “Sit down, for you have annoyed (people).” (Classed as sahih by al-Albani in Saheeh Abi Dawud)
The scholars differed concerning this matter and there are two views.
1 – That it is makruh. This was narrated by Ibn Al-Mundhir from the majority. Ibn Hajar said: The majority are of the view that it is makruh in the sense that it is better not to do it. This is the well-known view of the Shafai`is and is the view of the Hanbalis. (Fath al-Bari, 2/392; Kashshaf al-Qina’, 2/44; al-Majmu’, 4/466)
Malik and Al-Awza`i limited its being makruh to when the khateeb is on the pulpit. It says in Al-Mudawwanah (1/159): Malik said: Rather it is makruh to step over people when the imam has come out and has sat on the pulpit. Whoever steps over people then this is the one of whom the hadith speaks.
But before that there is nothing wrong with it if there is a gap in front of him, but he should be polite in doing that.
2– That stepping over others is haram in all cases, on Fridays and at other times, because of the hadith of `Abdullah ibn Busr mentioned above.
The preferred view
At-Tirmidhi said: This is what people should follow according to the scholars. They regarded it as makruh for a man to step over people on Friday, and they were very strict with regard to that.
This is what a number of scholars regarded as more likely to be correct, such as Ibn al-Mundhir, Ibn Abd al-Barr, al-Nawawi, and Imam Ibn Taymiyyah, as stated in al-Ikhtiyarat al-Fiqhiyyah, p. 81, and others. Among contemporary scholars who held this view is Shaykh Ibn ‘Uthaymeen.
Ibn al-Mundhir said, explaining the reason why he said it is haram: That is because causing annoyance is haram, whether it is a little or a lot, and this is causing annoyance, as it says in the hadith in which the Prophet (peace and blessings of Allah be upon him) said to one whom he saw stepping over people: “Sit down, for you are causing annoyance.” Al-Majmu’, 4/467.
Ibn Abd al-Barr said in al-Tamheed (1/316): The words of the Messenger of Allah to the one who was stepping over people on a Friday, “You are causing annoyance,” indicate that stepping over people is an annoyance, and it is not permissible to annoy a Muslim under any circumstances, on Friday or at any other time.
Al-Nawawi said in Rawdat al-Talibeen (11/224): The favored view is that stepping over people is haram, because of the hadiths on this topic.
Sheikh Ibn Uthaymeen said: Stepping over people is haram during the khutbah and at other times, because the Prophet said to a man whom he saw stepping over people: “Sit down, for you are causing annoyance.” That is even more forbidden if it happens during the khutbah, because it is causing annoyance to people and distracting them from listening to the khutbah, even if he is moving towards a gap. (Fatawa wa Rasa’il al-Shaykh Ibn `Uthaymeen, 16/147)
Almighty Allah knows best.