Ironport Email Security AppliancesHardware / appliance · Cisco
CVE-2014-8016
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 · uneditedThe Cisco IronPort Email Security Appliance (ESA) allows remote attackers to cause a denial of service (CPU consumption) via long Subject headers in e-mail messages, aka Bug ID CSCzv93864.
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 Cisco IronPort Email Security Appliance contains a denial of service vulnerability where processing email messages with excessively long Subject headers causes excessive CPU consumption, potentially rendering the appliance unresponsive and impacting email flow for all users.
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
Ironport Email Security AppliancesHardware / appliance
all versionsCVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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 device is a Cisco IronPort Email Security ApplianceLog into the ESA CLI and run 'version' or check the web interface header to identify the appliance modelAffected if The device is any model of Cisco IronPort Email Security Appliance (ESA)
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Identify the installed ESA software versionRun 'version' in the ESA CLI or check About page in the web interface to retrieve the installed AsyncOS versionAffected if Any version of Cisco AsyncOS for Email is installed (all versions are affected)
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Verify email processing is enabledRun 'mailconfig' or check the ESA web interface under Mail Flow > Inbound or Outbound to confirm email processing is activeAffected if Email receiving and processing is enabled (this is the default operational state)
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Check for existing Subject header length filtersRun 'filters' in the CLI or navigate to Mail Policies > Inbound/Outbound Filter in the web interface to inspect filter rulesAffected if No filter exists to limit or reject Subject headers exceeding a defined length threshold
If the device is a Cisco IronPort ESA with any AsyncOS version and email processing is active without Subject header length filtering, the environment is affected by this CVE.
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 dataApply the vendor patch or updated firmware for Cisco bug ID CSCzv93864. As a compensating control, implement email gateway filtering rules to reject or truncate Subject headers exceeding reasonable length limits before messages reach the ESA.
Fix this in Ironport Email Security Appliances
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2014-8016 — 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-2014-8016 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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- 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