CaptchaMind: Training CAPTCHA Solvers via Reinforcement Learning with Explicit Reasoning Supervision

Fuente: arXiv
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Main Authors: Wang, Pengcheng, Liu, Haoxiang, Dai, Yang, Zeng, Xiangxiang, Chen, Guanhua, Hu, Baotian, Wang, Longyue, Luo, Weihua
Format: Preprint
Published: 2026
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author Wang, Pengcheng
Liu, Haoxiang
Dai, Yang
Zeng, Xiangxiang
Chen, Guanhua
Hu, Baotian
Wang, Longyue
Luo, Weihua
author_facet Wang, Pengcheng
Liu, Haoxiang
Dai, Yang
Zeng, Xiangxiang
Chen, Guanhua
Hu, Baotian
Wang, Longyue
Luo, Weihua
contents CAPTCHAs are widely deployed as human verification mechanisms and frequently block intelligent agents from completing end-to-end automation in real-world web environments. Solving modern CAPTCHAs requires robust multi-step visual reasoning and interaction capabilities, yet training-based approaches have remained absent due to the lack of large-scale training data and process-level annotations. We introduce CaptchaBench, the first CAPTCHA benchmark designed to support large-scale training, comprising 16,000 programmatically generated samples across eight task categories with detailed region and process-level annotations. Systematic evaluation on CaptchaBench reveals that existing methods fail consistently on tasks requiring fine-grained visual detail capture and region-level comparison. We therefore present CaptchaMind, an RL-based solver trained with explicit reasoning process supervision, achieving 82.9% average success rate across eight tasks and 71.0% on real-world instances, substantially outperforming all existing methods without closed-source APIs.
format Preprint
id arxiv_https___arxiv_org_abs_2605_19538
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CaptchaMind: Training CAPTCHA Solvers via Reinforcement Learning with Explicit Reasoning Supervision
Wang, Pengcheng
Liu, Haoxiang
Dai, Yang
Zeng, Xiangxiang
Chen, Guanhua
Hu, Baotian
Wang, Longyue
Luo, Weihua
Computer Vision and Pattern Recognition
Artificial Intelligence
CAPTCHAs are widely deployed as human verification mechanisms and frequently block intelligent agents from completing end-to-end automation in real-world web environments. Solving modern CAPTCHAs requires robust multi-step visual reasoning and interaction capabilities, yet training-based approaches have remained absent due to the lack of large-scale training data and process-level annotations. We introduce CaptchaBench, the first CAPTCHA benchmark designed to support large-scale training, comprising 16,000 programmatically generated samples across eight task categories with detailed region and process-level annotations. Systematic evaluation on CaptchaBench reveals that existing methods fail consistently on tasks requiring fine-grained visual detail capture and region-level comparison. We therefore present CaptchaMind, an RL-based solver trained with explicit reasoning process supervision, achieving 82.9% average success rate across eight tasks and 71.0% on real-world instances, substantially outperforming all existing methods without closed-source APIs.
title CaptchaMind: Training CAPTCHA Solvers via Reinforcement Learning with Explicit Reasoning Supervision
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2605.19538