DRIFT: Derailing Denoising Trajectories of Flow-Matching VLAs with Adversarial Patch Attack

TaeHoseong, Jong-Seok Lee

DRIFT: Derailing Denoising Trajectories of Flow-Matching VLAs with Adversarial Patch Attack: 3 upvotes on Hugging Face Daily Papers, #31 of 34 papers on 2026-08-06. Day-by-day upvote history.

Flow-matching vision-language-action (VLA) models such as pi0 generate robot actions by integrating a learned denoising velocity field, and have been reported to resist adversarial perturbations that readily fool autoregressive VLAs. We show that this robustness is largely illusory: it stems from prior attacks ignoring the multi-step denoising ODE. We introduce DRIFT (Denoising Redirection via Input perturbation of the Flow-matching Trajectory), a test-time universal adversarial patch placed on the robot's gripper that attacks the denoising velocity field of an off-the-shelf policy. Our central finding is counterintuitive: attacking only the first denoising step is both stronger and cheaper than attacking a wider window of steps, which we explain through a gradient conflict unique to input-space optimization and which is exactly opposite to the training-time backdoor regime. On pi0 and pi0.5 across four LIBERO suites, DRIFT breaks essentially all originally-solvable tasks with a small single patch, far exceeding action- and embedding-space attack baselines.

Paper page on Hugging Face · arXiv

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