An issue was discovered in certain Apple products. macOS before 10.13.4 is affected. The issue involves the "Mail" component. It allows man-in-the-middle attackers to read S/MIME encrypted message content by sending HTML e-mail that references remote resources but lacks a valid S/MIME signature.
http://www.securityfocus.com/bid/103582
Source: MITRE
Published: 2018-04-03
Updated: 2020-08-24
Type: CWE-347
Base Score: 4.3
Vector: AV:N/AC:M/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 5.9
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Impact Score: 3.6
Exploitability Score: 2.2
Severity: MEDIUM