{"id":"CVE-2018-18509","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-18509","generatedAt":"2026-10-28T21:22:53.530Z","title":"The flaw allows an attacker to reuse a valid S/MIME signature to craft an email message with arbitrary content.","description":"A flaw during verification of certain S/MIME signatures causes emails to be shown in Thunderbird as having a valid digital signature, even if the shown message contents aren't covered by the signature. The flaw allows an attacker to reuse a valid S/MIME signature to craft an email message with arbitrary content. This vulnerability affects Thunderbird < 60.5.1.","published":"2019-04-26T17:29:00.000Z","lastModified":"2026-06-17T01:47:26.000Z","status":"Modified","sourceIdentifier":"security@mozilla.org","cvss":{"version":"3.0","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},"cwe":["CWE-347"],"affected":["mozilla/thunderbird"],"epss":{"score":0.01676,"percentile":0.76758,"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 (1.68%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00043.html","source":"security@mozilla.org"},{"url":"http://packetstormsecurity.com/files/152703/Johnny-You-Are-Fired.html","tags":["Third Party Advisory","VDB Entry"],"source":"security@mozilla.org"},{"url":"http://seclists.org/fulldisclosure/2019/Apr/38","tags":["Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"http://www.openwall.com/lists/oss-security/2019/04/30/4","tags":["Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:1144","source":"security@mozilla.org"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1507218","tags":["Issue Tracking","Permissions Required","Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://github.com/RUB-NDS/Johnny-You-Are-Fired","source":"security@mozilla.org"},{"url":"https://github.com/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.pdf","source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-06/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00043.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://packetstormsecurity.com/files/152703/Johnny-You-Are-Fired.html","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://seclists.org/fulldisclosure/2019/Apr/38","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2019/04/30/4","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:1144","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1507218","tags":["Issue Tracking","Permissions Required","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/RUB-NDS/Johnny-You-Are-Fired","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.pdf","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-06/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-18509","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."}