CVE-2018-12373

Name of the Vulnerable Software and Affected Versions Thunderbird versions prior to 52.9

Description The issue is related to the Secure/Multipurpose Internet Mail Extensions (S/MIME) function in the Thunderbird email client, which lacks protection for certain data. This can allow a remote attacker to gain unauthorized access to protected information when an email is forwarded or replied to. Specifically, decrypted S/MIME parts that are hidden using CSS or the plaintext HTML tag can leak plaintext when included in an HTML reply or forward.

Recommendations For versions prior to 52.9, update to version 52.9 or later to resolve the issue. As a temporary workaround, consider avoiding the use of HTML replies or forwards for emails containing sensitive S/MIME-protected information until the update is applied.