Enterprise LinuxOperating system · Redhat
CVE-2018-12372
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedDecrypted S/MIME parts, when included in HTML crafted for an attack, can leak plaintext when included in a a HTML reply/forward. This vulnerability affects Thunderbird < 52.9.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThis is an information disclosure vulnerability in Thunderbird where decrypted S/MIME email content can leak into HTML reply/forward messages. When a user replies to or forwards an HTML email containing specially crafted content that includes decrypted S/MIME parts, the plaintext can be exposed to unintended recipients or saved in plaintext form.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Enterprise LinuxOperating system
= 6.0= 7.0= 7.5= 7.6
Enterprise Linux DesktopOperating system
= 6.0= 7.0
Enterprise Linux ServerOperating system
= 6.0= 7.0
Enterprise Linux WorkstationOperating system
= 6.0= 7.0
Debian LinuxOperating system
= 8.0= 9.0
Ubuntu LinuxOperating system
= 14.04= 16.04= 17.10= 18.04< 52.9.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check Thunderbird versionOpen Thunderbird and go to Help > About Thunderbird, or run 'thunderbird --version' from command lineAffected if Version is earlier than 52.9.0 (for example, 52.8.0 or earlier)
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Verify S/MIME is configuredCheck Thunderbird Account Settings > Security for S/MIME certificate configuration, or inspect the Thunderbird profile directory for S/MIME key files in the cert8.db or key4.db databaseAffected if S/MIME encryption or signing certificates are configured and active on the account
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Confirm HTML composition is enabledIn Thunderbird, go to Account Settings > Composition & Addressing and check if 'Compose messages in HTML' is selectedAffected if HTML message composition is enabled (this allows the leak to occur in replies and forwards)
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Identify incoming S/MIME emailsExamine received emails in the account for S/MIME signed/encrypted messages - look for the lock icon or signature verification indicators in the message headerAffected if The user receives and decrypts S/MIME emails that contain HTML content
The user is affected if Thunderbird version is below 52.9.0 AND S/MIME is configured with HTML composition enabled, particularly when handling decrypted S/MIME content in HTML replies or forwards
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data52.9.0
Upgrade Thunderbird to version 52.9 or later to remediate this vulnerability.
Fix this in Enterprise Linux
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-12372 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-12372 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data