I know 'blame culture' is bad. I almost never blame anyone else. If there is a bug, even if created by someone else, i just fix it. I don't care who made it happen.

However, recently, a critical bug that may have costed the business hundreds of thousands of dollars was found. My manager, for the first time, said "(my name), it's really due to bad design". He didn't say it to the team, but he said my name and said it to me, in front of powerful managers higher up, like: VP of engineering, director of engineering.

Therefore, i am being blamed for this bug from the entire team. Yet, the code for this was designed by a colleague. Interestingly, he stayed silent while people were talking to me.

Should I stay professional and not say anything, just work on a solution? Or should I tell my manager that the design of this system was owned and developed by another colleague but i have no issue fixing it? I accept the blame that i should've noticed the bad design and suggested a re-design.