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iOSOperating system · Cisco

CVE-2012-4621

HIGH · 7.8 CVSS v2.0 Published 2012-09-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
87/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
The Device Sensor feature in Cisco IOS 15.0 through 15.2 allows remote attackers to cause a denial of service (device reload) via a DHCP packet, aka Bug ID CSCty96049.

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 confidence

The Device Sensor feature in Cisco IOS versions 15.0 through 15.2 contains a vulnerability where specially crafted DHCP packets sent by remote attackers can cause the affected device to reload, resulting in denial of service. This is an unauthenticated, network-adjacent attack requiring no user interaction.

MitigationUpgrade Cisco IOS to a version beyond 15.2 that contains the fix for CSCty96049. If immediate patching is not feasible, consider disabling the Device Sensor feature or implementing network segmentation to limit exposure to untrusted DHCP sources.

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
Affected:= 15.0= 15.0\(1\)se= 15.1= 15.2

CVSS 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
Complete

AV:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check the Cisco IOS version
    Execute 'show version' on the device and locate the version number in the output (typically the first line)
    Affected if The version is 15.0, 15.0(1)se, 15.1, or 15.2 (these are the affected versions)
  2. Verify if Device Sensor feature is enabled
    Execute 'show running-config | include device-sensor' or 'show device-sensor status' in privileged EXEC mode
    Affected if Device Sensor is enabled and the IOS version falls within the affected range (15.0-15.2)
  3. Confirm the device processes DHCP traffic
    Execute 'show ip dhcp pool' or 'show ip dhcp binding' to verify DHCP is configured and active on the device
    Affected if DHCP is actively configured on the device and the above version and feature conditions are met, the device is vulnerable to the crafted DHCP packet attack

You are affected if your Cisco IOS version is 15.0, 15.0(1)se, 15.1, or 15.2 AND the Device Sensor feature is enabled on the device.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Cisco IOS to a version beyond 15.2 that contains the fix for CSCty96049. If immediate patching is not feasible, consider disabling the Device Sensor feature or implementing network segmentation to limit exposure to untrusted DHCP sources.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2012-4621 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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