CVE-2018-18531: Kaptcha Project Kaptcha

Critical severity, CVSS 9.8. EPSS: 1.5% chance of exploitation in the next 30 days.

text/impl/DefaultTextCreator.java, text/impl/ChineseTextProducer.java, and text/impl/FiveLetterFirstNameTextCreator.java in kaptcha 2.3.2 use the Random (rather than SecureRandom) function for generating CAPTCHA values, which makes it easier for remote attackers to bypass intended access restrictions via a brute-force approach.

Affected products

• Kaptcha Project Kaptcha: version 2.3.2 only

Published 2018-10-19. Last modified 2026-06-17.