Debian LinuxOperating system · Debian
CVE-2017-17847
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 was discovered in Enigmail before 1.9.9. Signature spoofing is possible because the UI does not properly distinguish between an attachment signature, and a signature that applies to the entire containing message, aka TBE-01-021. This is demonstrated by an e-mail message with an attachment that is a signed e-mail message in message/rfc822 format.
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 confidenceEnigmail before version 1.9.9 contains a signature spoofing vulnerability where the UI fails to distinguish between a signature applied to an attachment versus a signature applied to the entire email message. An attacker can craft an email with a signed attachment in message/rfc822 format, misleading users into believing the entire message is authenticated when only the attachment is signed.
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
Debian LinuxOperating system
= 8.0= 9.0< 1.9.9CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 Enigmail is installedOpen Thunderbird, go to Add-ons Manager (Ctrl+Shift+A), or check for the Enigmail entry in the Thunderbird application menu under Extensions or Add-ons.Affected if Enigmail is listed as an installed extension
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Determine Enigmail version numberIn Thunderbird Add-ons Manager, click on Enigmail to view its details panel; the version number is displayed on that page.Affected if The version shown is lower than 1.9.9 (for example, 1.9.8, 1.9.7, etc.)
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Check for signed email handlingInspect any received emails that contain attachments in message/rfc822 format (nested emails). In Thunderbird, expand the attachment to view the nested message and check whether the Enigmail security banner shows a valid signature indicator.Affected if A signed attachment displays the same signature indicator as would appear for a fully signed message, without clear visual distinction that only the attachment (not the outer message) is signed
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Verify Debian package version if using system packageOn Debian systems, run: dpkg -l | grep enigmail or apt show enigmail to query the installed package version.Affected if The installed Enigmail package version is less than 1.9.9
You are affected if Enigmail is installed with a version below 1.9.9 and you handle PGP-signed emails containing message/rfc822 attachments, as the UI does not differentiate attachment signatures from message signatures.
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 data1.9.9
Upgrade to Enigmail 1.9.9 or later, which properly differentiates and displays signature status for attachments versus the full message content.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-17847 — 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-2017-17847 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