Biography: Imam Bukhari
Imam Bukhari was a Mujtahid
Allama Ismail Ajluni (Hanafi):

Statement by Allama Ismail Ajlouni Hanafi, the teacher of Ibn Abidin Shami Hanafi:

“He was a Mujtahid Mutlaq (an absolute independent jurist).” [Al-Fawaid al-Darari, referenced in Al-Kawthar al-Jari, p. 7]