iOSOperating system · Cisco
CVE-2014-3409
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 Ethernet Connectivity Fault Management (CFM) handling feature in Cisco IOS 12.2(33)SRE9a and earlier and IOS XE 3.13S and earlier allows remote attackers to cause a denial of service (device reload) via malformed CFM packets, aka Bug ID CSCuq93406.
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 · moderate confidenceThis is a denial of service vulnerability in Cisco IOS and IOS XE where malformed Ethernet Connectivity Fault Management (CFM) packets can cause the affected device to reload. The vulnerability exists in the CFM handling feature and can be exploited by remote attackers without authentication, leading to service disruption.
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
iOSOperating system
<= 12.2\(33\)sre9a
Ios XeOperating system
<= 3.13sCVSS 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
- Adjacent
- Complexity
- Low
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:A/AC:L/Au:N/C:N/I:N/A:C
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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Identify the IOS or IOS XE versionRun 'show version' or 'show version | include Version' to display the installed software versionAffected if The version falls within 12.2(33)SRE through 12.2(33)SRE9a for IOS, or 3.13S or earlier for IOS XE
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Verify if CFM is enabled on the deviceRun 'show ethernet cfm configuration' or 'show run | include ethernet cfm' to check for Ethernet CFM configurationAffected if CFM commands appear in the configuration, indicating the feature is active
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Check for CFM domain or maintenance domain configurationsRun 'show ethernet cfm domain' to list any configured CFM domainsAffected if Any CFM domains or maintenance domains are configured, meaning the device is processing CFM packets
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Identify interfaces with CFM enabledRun 'show ethernet cfm interfaces' or check interface configurations with 'show run | include interface' and look for 'ethernet cfm' linesAffected if CFM is enabled on any interface, exposing that interface to malformed packet exploitation
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Confirm the device is reachable on network segments handling CFM trafficReview network topology to determine if the device processes CFM packets from untrusted sources on affected interfacesAffected if The device processes CFM traffic from untrusted network segments on CFM-enabled interfaces
The device is affected if it runs a vulnerable IOS version (12.2(33)SRE through 12.2(33)SRE9a) or IOS XE version (3.13S or earlier) AND has CFM functionality enabled or configured on any interface.
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 appropriate Cisco patch for the specific IOS/IOS XE version. Until patches can be applied, consider implementing network segmentation or access controls to limit exposure to untrusted CFM packets on the affected interfaces.
Fix this in iOS
Scoped from the published advisory
- Consultation2.0 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-2014-3409 — 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-2014-3409 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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