Tell me about a time you were wrong about a security risk call.

Interviewers want self-awareness and growth, not perfection. Pick a real call (e.g. over- or under-rating a finding), explain your reasoning at the time, what new information changed it, the impact, and — most importantly — the process change you made so the mistake is less likely again (better data, a second reviewer, a clearer rubric). Own it without being defensive.