iOSOperating system · Cisco
CVE-2014-3293
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 · uneditedCisco IOS 15.4(3)S0b on ASR901 devices makes incorrect decisions to use the CPU for IPv4 packet processing, which allows remote attackers to cause a denial of service (BGP neighbor flapping) by sending many crafted IPv4 packets, aka Bug ID CSCuo29736.
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 confidenceCisco IOS 15.4(3)S0b on ASR901 devices contains a logic error where the system incorrectly routes IPv4 packet processing to the CPU instead of hardware forwarding. Attackers can exploit this by sending specially crafted IPv4 packets in volume, causing CPU exhaustion that leads to BGP neighbor session flapping and resulting in denial of service.
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
= 15.4\(3\)s0b
Asr901Hardware / 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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Identify the device modelRun 'show version' or 'show inventory' and look for 'ASR901' in the outputAffected if The device model is Cisco ASR901 series
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Check the IOS versionRun 'show version' and look at the 'IOS (tm)' or 'software' line. Identify the exact version number (for example: 15.4(3)S0b)Affected if The IOS version is 15.4(3)S0b specifically, or is an earlier unreleased build of 15.4(3)S before the fix was applied
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Verify IPv4 routing is enabledRun 'show ip protocols' or check the running configuration for 'ip routing' under the global configurationAffected if IPv4 routing is enabled on the device (this is required for the vulnerability to be triggerable)
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Confirm BGP is configuredRun 'show ip bgp summary' or 'show bgp all' to check for BGP neighbor configurationsAffected if BGP is configured and running (BGP sessions will be impacted by CPU exhaustion)
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Check CPU utilization and packet processingRun 'show processes cpu history' and 'show platform cpu packet statistics' if available. Look for unusually high CPU usage or packets being punted to CPUAffected if CPU utilization is abnormally high with IPv4 traffic, indicating packets are being processed by CPU rather than hardware forwarding
The device is affected if it is an ASR901 running Cisco IOS version 15.4(3)S0b (or an unreleased earlier build) with IPv4 routing enabled, causing IPv4 packets to be forwarded to CPU instead of hardware.
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 to a patched Cisco IOS version for the ASR901 platform. As an interim control, implement ingress traffic rate limiting or ACLs on upstream devices to reduce exposure to malicious packet streams.
Fix this in iOS
Scoped from the published advisory
- Consultation3.0 h
- Implementation2.0 h
- Testing4.0 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 $3,072.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2014-3293 — 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-2014-3293 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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- Version or environment caveats, and links to real fixes
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