CVE-2019-11739

Mozilla: Covert Content Attack on S/MIME encryption using a crafted multipart/alternative message

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Severity

Important

Red Hat Product Security

6.5

CVSS 3.1

Review impact separately from score.

Published · September 15, 2019

Updated · January 9, 2026

Description

Encrypted S/MIME parts in a crafted multipart/alternative message can leak plaintext when included in a a HTML reply/forward. This vulnerability affects Thunderbird < 68.1 and Thunderbird < 60.9.

Statement

In general, this flaw cannot be exploited through email in Thunderbird because scripting is disabled when reading mail, but it may present a risk in browser-like contexts.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CWE-356 · Product UI does not Warn User of Unsafe Actions