CVE-2018-18531

9.8 criticalEPSS 1.5%

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.

Severity

CVSS 3.0

9.8 critical

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 1.5% chance of exploitation in the next 30 days; higher than 73% of CVEs (scores of 2026-10-31)
CWE: CWE-330
Published: 2018-10-19
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

kaptcha_project:kaptcha

Packages (OSV)

Advisory	Ecosystem	Package	Affected	Fixed in
GHSA-8q89-pwhh-7wfq	Maven	com.github.penggle:kaptcha	<=2.3.2	no fix published

References

https://github.com/penggle/kaptcha/issues/3
https://github.com/penggle/kaptcha/issues/3

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