{"id":"CVE-2020-13998","aliases":["EUVD-2020-6167","GHSA-5x67-frfj-mmvh"],"status":"published","title":"** VERSION NOT SUPPORTED WHEN ASSIGNED ** Citrix XenApp 6.5, when 2FA is enabled, allows a remote...","description":"Citrix XenApp 6.5, when 2FA is enabled, allows a remote unauthenticated attacker to ascertain whether a user exists on the server, because the 2FA error page only occurs after a valid username is entered. NOTE: This vulnerability only affects products that are no longer supported by the maintainer","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-11","score":0.01424,"percentile":0.73251,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-200","CWE-203","CWE-639"],"published":"2020-06-11T01:59:35Z","modified":"2026-06-17T02:54:04Z","products":[{"vendor":"citrix","product":"xenapp"}],"references":[{"url":"https://gist.github.com/kampji/11e259d68ad98a6f0f898132f1961a96","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-13998"},{"url":"https://github.com/advisories/GHSA-5x67-frfj-mmvh"}],"sources":{"cve":[{"id":"CVE-2020-13998","description":"Citrix XenApp 6.5, when 2FA is enabled, allows a remote unauthenticated attacker to ascertain whether a user exists on the server, because the 2FA error page only occurs after a valid username is entered. NOTE: This vulnerability only affects products that are no longer supported by the maintainer","status":"published","published":"2020-06-11T01:59:35Z","modified":"2024-08-04T12:32:14.84Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high","assessor":"adp"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T14:35:53.868619Z"}],"euvd":[{"id":"EUVD-2020-6167","description":"Citrix XenApp 6.5, when 2FA is enabled, allows a remote unauthenticated attacker to ascertain whether a user exists on the server, because the 2FA error page only occurs after a valid username is entered. NOTE: This vulnerability only affects products that are no longer supported by the maintainer","status":"published","published":"2020-06-11T01:59:35Z","modified":"2024-08-04T12:32:14Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high"}],"updated_at":"2026-11-03T03:07:35.697348Z"}],"ghsa":[{"id":"GHSA-5x67-frfj-mmvh","title":"** VERSION NOT SUPPORTED WHEN ASSIGNED ** Citrix XenApp 6.5, when 2FA is enabled, allows a remote...","description":"** VERSION NOT SUPPORTED WHEN ASSIGNED ** Citrix XenApp 6.5, when 2FA is enabled, allows a remote unauthenticated attacker to ascertain whether a user exists on the server, because the 2FA error page only occurs after a valid username is entered.","status":"published","published":"2022-05-24T17:20:22Z","modified":"2024-08-01T15:31:15Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-200","CWE-203","CWE-639"],"updated_at":"2026-11-02T14:57:46.205602Z"}],"nvd":[{"id":"CVE-2020-13998","description":"Citrix XenApp 6.5, when 2FA is enabled, allows a remote unauthenticated attacker to ascertain whether a user exists on the server, because the 2FA error page only occurs after a valid username is entered. NOTE: This vulnerability only affects products that are no longer supported by the maintainer","status":"published","published":"2020-06-11T02:15:10.713Z","modified":"2026-06-17T02:54:04.447Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"primary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high","assessor":"secondary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-203","CWE-639"],"updated_at":"2026-11-02T14:06:05.962132Z"}]}}