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10008 RouterHardware / appliance · Cisco

CVE-2012-4620

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
Cisco IOS 12.2 and 15.0 through 15.2 on Cisco 10000 series routers, when a tunnel interface exists, allows remote attackers to cause a denial of service (interface queue wedge) via tunneled (1) GRE/IP, (2) IPIP, or (3) IPv6 in IPv4 packets, aka Bug ID CSCts66808.

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

Cisco IOS 12.2 and 15.0 through 15.2 on Cisco 10000 series routers contains a vulnerability where the presence of a tunnel interface allows remote attackers to cause a denial of service by sending specially crafted tunneled packets (GRE/IP, IPIP, or IPv6 in IPv4), which wedges the interface queue and renders it unresponsive.

MitigationRemove or disable unnecessary tunnel interfaces on affected routers, and apply the Cisco IOS update that addresses CSCts66808. If tunnels are required, implement ACLs to restrict tunneled traffic to trusted 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
10008 RouterHardware / appliance
Affected:all versions
iOSOperating system
Affected:= 12.2= 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. Identify router model
    Run 'show version' or check hardware inventory to confirm the device is a Cisco 10000 series router (specifically 10008)
    Affected if Router model is NOT Cisco 10008 or 10000 series
  2. Check IOS version
    Run 'show version' and locate the IOS version in the output. Compare against affected versions: 12.2, 15.0, 15.0(1)se, 15.1, 15.2
    Affected if IOS version is NOT in the 12.2, 15.0-15.2 range
  3. List configured tunnel interfaces
    Run 'show ip interface brief' or 'show interface tunnel' to list all tunnel interfaces configured on the router
    Affected if NO tunnel interfaces are configured (no tunnels = not vulnerable)
  4. Verify tunnel type
    For each tunnel interface, run 'show interface tunnel<X>' and confirm the tunnel mode: GRE/IP, IPIP, or IPv6-in-IPv4
    Affected if Tunnel mode is NOT GRE, IPIP, or IPv6-in-IPv4 (other tunnel types may not be affected)

Router is affected if it is a Cisco 10008/10000 series, runs IOS 12.2 through 15.2, AND has at least one GRE, IPIP, or IPv6-in-IPv4 tunnel interface configured and active.

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

Remove or disable unnecessary tunnel interfaces on affected routers, and apply the Cisco IOS update that addresses CSCts66808. If tunnels are required, implement ACLs to restrict tunneled traffic to trusted sources.

Fix this in 10008 Router Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2012-4620 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