{"id":"CVE-2018-4221","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-4221","generatedAt":"2026-10-28T20:12:33.348Z","title":"It allows web sites to track users by leveraging the transmission of S/MIME client certificates.","description":"An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. The issue involves the \"Security\" component. It allows web sites to track users by leveraging the transmission of S/MIME client certificates.","published":"2018-06-08T18:29:01.000Z","lastModified":"2026-06-17T01:58:37.000Z","status":"Modified","sourceIdentifier":"product-security@apple.com","cvss":{"version":"3.0","score":7.5,"severity":"HIGH","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},"cwe":["CWE-200"],"affected":["apple/iphone os","apple/mac os x"],"epss":{"score":0.01224,"percentile":0.68635,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (1.22%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"http://www.securityfocus.com/bid/104897","tags":["Third Party Advisory","VDB Entry"],"source":"product-security@apple.com"},{"url":"http://www.securitytracker.com/id/1041027","tags":["Third Party Advisory","VDB Entry"],"source":"product-security@apple.com"},{"url":"https://support.apple.com/HT208848","tags":["Vendor Advisory"],"source":"product-security@apple.com"},{"url":"https://support.apple.com/HT208849","tags":["Vendor Advisory"],"source":"product-security@apple.com"},{"url":"http://www.securityfocus.com/bid/104897","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id/1041027","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/HT208848","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/HT208849","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-4221","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}