CVE-2020-12398

7.5 highEPSS 1.0%

High (7.5). EPSS 1.0% chance of exploitation in the next 30 days.

If Thunderbird is configured to use STARTTLS for an IMAP server, and the server sends a PREAUTH response, then Thunderbird will continue with an unencrypted connection, causing email data to be sent without protection. This vulnerability affects Thunderbird < 68.9.0.

Severity

CVSS 3.1

7.5 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS: 1.0% chance of exploitation in the next 30 days; higher than 62% of CVEs (scores of 2026-10-31)
CWE: CWE-319
Published: 2020-07-09
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

canonical:ubuntu_linux
mozilla:thunderbird

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1613623
https://usn.ubuntu.com/4421-1/
https://www.mozilla.org/security/advisories/mfsa2020-22/
https://bugzilla.mozilla.org/show_bug.cgi?id=1613623
https://usn.ubuntu.com/4421-1/

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