What’s Vulnerable › Vulnerabilities

CVE-2018-12373

• Severity: medium (CVSS 6.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-10-18 · updated 2026-06-17
• Weakness: CWE-200

Description

dDecrypted S/MIME parts hidden with CSS or the plaintext HTML tag can leak plaintext when included in a HTML reply/forward. This vulnerability affects Thunderbird < 52.9.

Affected products

• Canonical Ubuntu Linux: 14.04, 16.04, 17.10, 18.04
• Debian Linux: 8.0, 9.0
• Mozilla Thunderbird: before 52.9.0 — fixed in 52.9.0
• Red Hat Enterprise Linux: 6.0, 7.0, 7.5, 7.6
• RedHat Enterprise Linux Desktop: 6.0, 7.0
• RedHat Enterprise Linux Server: 6.0, 7.0
• RedHat Enterprise Linux Workstation: 6.0, 7.0

How to fix

Upgrade to a fixed version: Mozilla Thunderbird 52.9.0. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/104613
• https://access.redhat.com/errata/RHSA-2018:2251
• https://access.redhat.com/errata/RHSA-2018:2252
• https://bugzilla.mozilla.org/show_bug.cgi?id=1464056
• https://bugzilla.mozilla.org/show_bug.cgi?id=1464667
• https://lists.debian.org/debian-lts-announce/2018/07/msg00013.html
• https://security.gentoo.org/glsa/201811-13
• https://usn.ubuntu.com/3714-1/
• https://www.debian.org/security/2018/dsa-4244
• https://www.mozilla.org/security/advisories/mfsa2018-18/
• http://www.securityfocus.com/bid/104613
• https://access.redhat.com/errata/RHSA-2018:2251

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