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Nx OsOperating system · Cisco

CVE-2013-1211

MEDIUM · 5.0 CVSS v2.0 Published 2013-05-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
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 NX-OS on the Nexus 1000V does not properly handle authentication for Virtual Ethernet Module (VEM) to Virtual Supervisor Module (VSM) communication, which allows remote attackers to obtain VEM access via (1) spoofed STUN packets or (2) a crafted VMware ESXi instance, aka Bug ID CSCud14832.

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 confidence

Cisco NX-OS on the Nexus 1000V fails to properly authenticate Virtual Ethernet Module (VEM) to Virtual Supervisor Module (VSM) communications, allowing remote attackers to spoof STUN packets or deploy a crafted VMware ESXi instance to gain unauthorized VEM access.

MitigationApply the Cisco patch for Bug ID CSCud14832 when available; otherwise, implement network segmentation and ACLs to restrict traffic to VSM management interfaces and block unauthorized STUN traffic.

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
Nx OsOperating system
Affected:all versions

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
Partial
Availability
None

AV:N/AC:L/Au:N/C:N/I:P/A:N

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 Nexus 1000V deployment
    Run 'show version' or 'show module' to confirm the device is a Cisco Nexus 1000V running NX-OS
    Affected if The system is a Nexus 1000V virtual switch running NX-OS
  2. Check VEM-VSM communication status
    Run 'show vem status' or 'show module vem' to verify if Virtual Ethernet Modules are connected to the Virtual Supervisor Module
    Affected if VEM modules are actively connected to the VSM
  3. Verify STUN protocol configuration
    Run 'show stun' or 'show running-config | include stun' to check if STUN (Serial Tunnel) protocol is enabled for VEM-VSM communication
    Affected if STUN protocol is configured and active for VEM communication
  4. Inspect VSM management interface access controls
    Run 'show running-config interface mgmt0' and check ACLs or security policies applied to the VSM management interface
    Affected if Management interface lacks restrictive ACLs or is accessible from untrusted networks
  5. Check for unauthorized VEM registration attempts
    Run 'show vem license' and 'show module' to verify only authorized VEMs are registered with the VSM
    Affected if Unknown or unauthorized VEMs appear in the module list

The environment is affected if it runs Cisco NX-OS on Nexus 1000V with VEM-VSM communication enabled and STUN in use, particularly if the VSM management interface is not protected by restrictive ACLs.

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

Apply the Cisco patch for Bug ID CSCud14832 when available; otherwise, implement network segmentation and ACLs to restrict traffic to VSM management interfaces and block unauthorized STUN traffic.

Fix this in Nx Os 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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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-2013-1211 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
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