CVE-2019-8645
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 · uneditedAn issue existed in the handling of encrypted Mail. This issue was addressed with improved isolation of MIME in Mail. This issue is fixed in macOS Mojave 10.14.4, Security Update 2019-002 High Sierra, Security Update 2019-002 Sierra. An attacker in a privileged network position may be able to intercept the contents of S/MIME-encrypted e-mail.
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 confidenceThe vulnerability exists in macOS Mail's handling of S/MIME encrypted MIME content. The issue allowed an attacker with privileged network position (MITM) to intercept plaintext of encrypted emails due to improper MIME isolation in the Mail application, bypassing the S/MIME encryption protection.
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< 10.14.4CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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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Verify macOS versionClick Apple menu > About This Mac to display the macOS version numberAffected if The reported version is earlier than 10.14.4 (Mojave) or the build number is lower than the build included in 10.14.4
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Confirm macOS Mail is in useLaunch Mail application or check for /Applications/Mail.app in the filesystemAffected if Mail.app is present and has been used to handle email
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Determine if S/MIME encryption is configuredOpen Mail > Preferences > Accounts > select an account > Account Information > check for S/MIME settings or certificates configured under the Security tabAffected if S/MIME signing or encryption is enabled for any mail account in the application
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Check for inbound encrypted MIME contentInspect recent email messages in Mail for messages that show as S/MIME encrypted (typically indicated by a lock icon or encrypted content display)Affected if The system has received and processed S/MIME encrypted email messages using the built-in Mail application
The environment is affected if macOS version is below 10.14.4, Mail app is used, S/MIME encryption is configured, and the system has processed S/MIME encrypted messages.
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 data10.14.4
Apply the relevant Apple security updates (macOS Mojave 10.14.4, Security Update 2019-002 High Sierra, or Security Update 2019-002 Sierra) to affected systems.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-8645 — 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-2019-8645 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