StepJack (Single-Step): leaderboard

StepJack (2026) tests whether computer-use agents carry out an adversarial goal planted in web pages or documents they visit while doing a benign task for the user; an environment-state checker decides whether the goal was achieved. Here the injection is a single instruction. Score is the attack success rate in percent; lower is better.

Metric: Attack success rate (%, lower is better; share of examples whose environment-state checker finds the adversarial goal achieved; the goal injected as one instruction, k = 1; each computer-use agent in its default OSWorld agent implementation with 15 x k actions, on StepJack tasks in Reddit and OwnCloud environments with 12 adversarial goals; no urgency cue; one run). Source: arxiv.org. Saturation forecast: Around July 2027. 6 models tracked.

Top models

#ModelScoreOverall rank
1Claude Haiku 4.512.5#568
2Claude Sonnet 4.620.8#161
3Qwen 3.5 Plus29.2#232
4GPT-5.4 Mini (xHigh)41.7#389 (GPT-5.4 Mini)
5Kimi K2.552.1#256

No result here: #1 Claude Fable 5.2, #2 Gemini 4 Carbon, #5 Claude Opus 5.5.

Interactive version: theaggregate.ai/benchmark?slug=stepjack-single-step · How It Works · Data refreshed daily, snapshot 2026-11-13.