{"cve":"CVE-2021-38502","nvd":{"published":"2021-11-03T01:15:07.657","modified":"2026-06-17T04:02:14.287","status":"Modified","description":"Thunderbird ignored the configuration to require STARTTLS security for an SMTP connection. A MITM could perform a downgrade attack to intercept transmitted messages, or could take control of the authenticated session to execute SMTP commands chosen by the MITM. If an unprotected authentication method was configured, the MITM could obtain the authentication credentials, too. This vulnerability affects Thunderbird < 91.2.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","score":5.9},"cwes":[],"references":["https://bugzilla.mozilla.org/show_bug.cgi?id=1733366","https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html","https://www.debian.org/security/2022/dsa-5034","https://www.mozilla.org/security/advisories/mfsa2021-47/","https://bugzilla.mozilla.org/show_bug.cgi?id=1733366"],"products":["debian:debian_linux","mozilla:thunderbird"],"source":"nvd","synced_at":"2026-10-19T21:24:39.218183596+00:00"},"epss":{"cve":"CVE-2021-38502","score":0.01101,"percentile":0.65705,"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."]}