Confound from all Sides, Distill with Resilience: Multi-Objective Adversarial Paths to Zero-Shot Robustness

Adversarially robust knowledge distillation transfers the robustness of a large-scale teacher model to a lightweight student while preserving natural performance. However, foundation Vision-Language Models (VLMs) also demand the transfer of zero-shot inference capabilities. We find that standard robust distillation using untargeted adversarial examples fails to transfer out-of-distribution (zero-shot) robustness, as these adversaries primarily push inputs away from their original distribution, exploring a limited portion of the teacher's decision space and missing more diverse failure modes. A natural solution is to generate multiple targeted adversaries that traverse diverse paths across decision boundaries. Thus, these adversaries probe a broader region of the teacher's decision surface. However, naive targeted adversary optimization often converges to local optima within a single category's decision region, limiting the diversity. To address this, we propose a Multi-Objective Optimization (MOO)-based adversarial distillation framework that transfers robustness from large VLMs to lightweight ones by exploiting adversaries with two main objectives: misclassification and category-level adversarial diversity. Theoretically, we show that optimizing for diversity mitigates adversarial collapse into local optima, ensuring adversaries span multiple decision regions and capture the teacher's generalizable robust features. Extensive experiments demonstrate the superiority of our method over stateof-the-art adversarial learning across diverse scenarios.