{"id":"CVE-2018-18531","aliases":["EUVD-2018-0553","GHSA-8q89-pwhh-7wfq"],"status":"published","title":"Use of Insufficiently Random Values in penggle:kaptcha","description":"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":{"version":"3.0","score":9.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.01468,"percentile":0.73893,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-330"],"published":"2018-10-19T20:00:00Z","modified":"2026-06-17T01:47:27Z","affected":[{"source":"ghsa","ecosystem":"Maven","package":"com.github.penggle:kaptcha","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.3.2"}]}]},{"source":"osv","ecosystem":"Maven","package":"com.github.penggle:kaptcha","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.3.2"}]}],"versions":["2.3.2"]}],"products":[{"vendor":"kaptcha_project","product":"kaptcha"}],"references":[{"url":"https://github.com/penggle/kaptcha/issues/3","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2018-18531","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-8q89-pwhh-7wfq","tags":["advisory"]},{"url":"https://github.com/penggle/kaptcha","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2018-18531","description":"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.","status":"published","published":"2018-10-19T20:00:00Z","modified":"2024-09-17T04:10:30.464Z","updated_at":"2026-11-02T14:35:11.426178Z"}],"euvd":[{"id":"EUVD-2018-0553","description":"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.","status":"published","published":"2018-10-19T20:00:00Z","modified":"2024-09-17T04:10:30Z","updated_at":"2026-11-03T00:28:25.314109Z"}],"ghsa":[{"id":"GHSA-8q89-pwhh-7wfq","title":"Use of Insufficiently Random Values in penggle:kaptcha","description":"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.","status":"published","published":"2018-10-23T16:08:56Z","modified":"2023-01-09T05:03:31Z","cvss":[{"version":"3.0","score":9.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-330"],"updated_at":"2026-11-02T14:36:05.071174Z"}],"nvd":[{"id":"CVE-2018-18531","description":"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.","status":"published","published":"2018-10-19T20:29:00.57Z","modified":"2026-06-17T01:47:27.823Z","cvss":[{"version":"3.0","score":9.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-330"],"updated_at":"2026-11-02T14:04:46.409324Z"}],"osv":[{"id":"GHSA-8q89-pwhh-7wfq","title":"Use of Insufficiently Random Values in penggle:kaptcha","description":"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.","status":"published","published":"2018-10-23T16:08:56Z","modified":"2023-11-08T04:00:05.731213Z","cvss":[{"version":"3.0","score":9.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-330"],"updated_at":"2026-11-02T15:46:42.78452Z"}]}}