Email Security Appliance FirmwareApplication · Cisco
CVE-2017-6671
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 · uneditedA vulnerability in the email message scanning of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass configured filters on the device, as demonstrated by the Attachment Filter. More Information: CSCvd34632. Known Affected Releases: 10.0.1-087 9.7.1-066. Known Fixed Releases: 10.0.2-020 9.8.1-015.
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 confidenceA vulnerability in the email message scanning function of Cisco AsyncOS Software for the Cisco Email Security Appliance (ESA) allows an unauthenticated, remote attacker to bypass configured filters on the device, such as the Attachment Filter, potentially allowing malicious attachments or content to pass through unchecked.
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
Email Security Appliance FirmwareApplication
= 9.7.1-066= 10.0.1-087CVSS 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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Confirm Cisco ESA deviceAccess the ESA web interface or CLI and verify the device model is Cisco Email Security Appliance. In CLI, run 'version' or 'show version' to see device information.Affected if The device is not a Cisco Email Security Appliance (not affected)
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Check AsyncOS firmware versionIn ESA CLI, run the 'version' or 'show version' command. In the web interface, navigate to System Administration > Software Upgrade or About page to view the installed AsyncOS version.Affected if The installed version is exactly 9.7.1-066 or exactly 10.0.1-087
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Verify content filters are configuredIn the ESA web interface, go to Mail Policies > Incoming Mail Policies or Outgoing Mail Policies. Check if Attachment Filter, Content Filter, or Message Filter policies are enabled. In CLI, run 'filters' or 'show filters' to list configured filters.Affected if Content/filters are NOT configured (the bypass has no impact since no filters exist to bypass)
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Inspect filter rules for attachment/content scanningReview the configured filter rules to confirm they include attachment scanning or content inspection. Look for filter conditions such as 'attachment', 'filetype', 'mime-type', or content keywords.Affected if Filters are configured but do not include attachment or content scanning (the specific bypass does not apply)
A user is affected only if they have a Cisco ESA running exactly version 9.7.1-066 or 10.0.1-087 AND have configured content/attachment filters that could be bypassed.
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 dataUpgrade Cisco AsyncOS Software on the ESA to fixed release 10.0.2-020 or 9.8.1-015 to remediate this vulnerability.
Fix this in Email Security Appliance Firmware
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 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 $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-6671 — 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-2017-6671 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
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