{"cve":"CVE-2018-18509","nvd":{"published":"2019-04-26T17:29:00.243","modified":"2026-06-17T01:47:25.993","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-347"],"references":["http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00043.html","http://packetstormsecurity.com/files/152703/Johnny-You-Are-Fired.html","http://seclists.org/fulldisclosure/2019/Apr/38","http://www.openwall.com/lists/oss-security/2019/04/30/4","https://access.redhat.com/errata/RHSA-2019:1144"],"products":["mozilla:thunderbird"],"source":"nvd","synced_at":"2026-10-19T20:56:19.218283075+00:00"},"epss":{"cve":"CVE-2018-18509","score":0.01676,"percentile":0.76883,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}