{"id":"CVE-2018-20187","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-20187","generatedAt":"2026-10-28T20:08:33.475Z","title":"An attacker capable of precisely measuring the time taken for ECC key generation may be able to derive information about the high bits of the secret key, as the function to derive the public point from the secret scalar uses an unblinded Montgomery…","description":"A side-channel issue was discovered in Botan before 2.9.0. An attacker capable of precisely measuring the time taken for ECC key generation may be able to derive information about the high bits of the secret key, as the function to derive the public point from the secret scalar uses an unblinded Montgomery ladder whose loop iteration count depends on the bitlength of the secret. This issue affects only key generation, not ECDSA signatures or ECDH key agreement.","published":"2019-03-08T19:29:00.000Z","lastModified":"2026-06-17T01:52:26.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.0","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},"cwe":["CWE-320"],"affected":["botan project/botan"],"epss":{"score":0.01525,"percentile":0.74539,"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":"low","text":"Lower severity and a low EPSS score (1.52%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://botan.randombit.net/news.html","tags":["Release Notes","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://botan.randombit.net/security.html","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/crocs-muni/ECTester","tags":["Not Applicable","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://botan.randombit.net/news.html","tags":["Release Notes","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://botan.randombit.net/security.html","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/crocs-muni/ECTester","tags":["Not Applicable","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-20187","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."}