1000v Virtual Ethernet Module \(vem\)Plugin / extension · Cisco
CVE-2011-0355
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 Nexus 1000V Virtual Ethernet Module (VEM) 4.0(4) SV1(1) through SV1(3b), as used in VMware ESX 4.0 and 4.1 and ESXi 4.0 and 4.1, does not properly handle dropped packets, which allows guest OS users to cause a denial of service (ESX or ESXi host OS crash) by sending an 802.1Q tagged packet over an access vEthernet port, aka Cisco Bug ID CSCtj17451.
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 confidenceA denial of service vulnerability in Cisco Nexus 1000V Virtual Ethernet Module (versions 4.0(4) SV1(1) through SV1(3b)) occurs when the VEM improperly handles 802.1Q tagged packets sent over access vEthernet ports. When guest OS users send VLAN-tagged packets on access ports (which should not accept tags), the mishandling of these dropped packets causes the underlying ESX or ESXi host OS to crash.
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
1000v Virtual Ethernet Module \(vem\)Plugin / extension
= 4.0\(4\)
EsxApplication
= 4.0= 4.1
EsxiApplication
= 4.0= 4.1CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify Cisco Nexus 1000V VEM installationRun 'show module' or 'show version' on the Nexus 1000V Virtual Supervisor Module to confirm the Virtual Ethernet Module (VEM) is installedAffected if The VEM module is not present, so the vulnerability does not apply
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Check VEM software versionRun 'show module' or 'show version' and locate the VEM software version (format: 4.0(4)SV1(x))Affected if Version is 4.0(4) SV1(1), SV1(2), or SV1(3b) - the affected range before the fix
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Verify ESX/ESXi host versionRun 'vmware -v' on the ESX/ESXi host or check via vClient/vSphere inventoryAffected if Host runs ESX 4.0, ESX 4.1, ESXi 4.0, or ESXi 4.1 in combination with the affected VEM version
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Confirm access vEthernet port configurationRun 'show interface virtual' or 'show running-config' to identify vEthernet interfaces configured as access ports (switchport mode access)Affected if Access vEthernet ports are configured, allowing guest VMs to potentially send 802.1Q tagged packets that trigger the crash
Environment is affected if Cisco Nexus 1000V VEM version 4.0(4) SV1(1) through SV1(3b) is running on ESX/ESXi 4.0/4.1 with access vEthernet ports configured where guest VMs can send VLAN-tagged packets
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 version of Cisco Nexus 1000V beyond SV1(3b) that properly handles 802.1Q tagged packets on access ports; alternatively, implement network segmentation or access control lists to prevent guest VMs from sending tagged packets to access ports.
Fix this in 1000v Virtual Ethernet Module \(vem\)
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-0355 — 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-2011-0355 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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