Black & White Path

Jun 25, 2026 · Information Security

Captcha Reuse Vulnerabilities: Real-World Exploits and Bypass Techniques

The article presents four practical case studies of captcha-related weaknesses—two showing how verifyId or UUID reuse lets attackers bypass image verification, one demonstrating a UUID‑bound bypass, and a fourth exposing a resource‑consumption flaw via manipulable height and width parameters.