Nx OsOperating system · Cisco

CVE-2011-4023

HIGH · 7.8 CVSS v2.0 Published 2012-05-03

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

NVD · unedited

Memory leak in libcmd in Cisco NX-OS 5.0 on Nexus switches allows remote authenticated users to cause a denial of service (memory consumption) via SNMP requests, aka Bug ID CSCtr65682.

Technical summary

dbcve analysis · moderate confidence

Memory leak in the libcmd component of Cisco NX-OS 5.0 on Nexus switches. Remote authenticated users can trigger the leak by sending specially crafted SNMP requests, causing progressive memory consumption that leads to denial of service through system exhaustion.

MitigationApply the Cisco patch for Bug ID CSCtr65682, which typically involves updating to a fixed NX-OS version. If immediate patching is not feasible, restrict SNMP access to trusted management networks and monitor memory usage closely.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions

NVD · CPE data

Nx OsOperating system

Affected:= 5.0= 5.0$2$= 5.0$2$n1$1$= 5.0$2$n2$1$= 5.0$2$n2$1a$= 5.0$2a$= 5.0$3$= 5.0$3$n1$1$= 5.0$3$n1$1a$= 5.0$3$n1$1b$= 5.0$3$n1$1c$= 5.0$3$n2$1$

Nexus 2148t Fex SwitchHardware / appliance

Affected:all versions

Nexus 2224tp Fex SwitchHardware / appliance

Affected:all versions

Nexus 2232pp Fex SwitchHardware / appliance

Affected:all versions

Nexus 2232tm Fex SwitchHardware / appliance

Affected:all versions

Nexus 2248tp E Fex SwitchHardware / appliance

Affected:all versions

Nexus 2248tp Fex SwitchHardware / appliance

Affected:all versions

Nexus 5010p SwitchHardware / appliance

Affected:all versions

CVSS breakdown

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?

dbcve checks

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

Identify the NX-OS version

Run 'show version' or check the system banner to determine the exact NX-OS version installed on the switch

Affected if The version matches any of: 5.0, 5.0(2), 5.0(2)n1(1), 5.0(2)n2(1), 5.0(2)n2(1a), 5.0(2a), 5.0(3), 5.0(3)n1(1), 5.0(3)n1(1a), 5.0(3)n1(1b), 5.0(3)n1(1c), or 5.0(3)n2(1)
Identify the switch model

Run 'show version' or 'show inventory' to identify the exact model number of the Nexus switch

Affected if The model is any of: Nexus 2148t, 2224tp, 2232pp, 2232tm, 2248tp E, 2248tp, 5010p, or any FEX switch (these are affected at all versions)
Verify SNMP configuration status

Run 'show snmp' or check the SNMP configuration to determine if SNMP is enabled on the device

Affected if SNMP is enabled and accessible from network locations where remote authenticated users can send requests
Check current system memory usage

Run 'show system resources' or 'show memory' to view current memory consumption

Affected if Memory usage is abnormally high or progressively increasing without an obvious cause
Review SNMP access controls

Run 'show snmp community' and check SNMP ACLs to determine who can send SNMP requests to the device

Affected if SNMP is accessible to untrusted or overly broad network ranges

The environment is affected if the device runs NX-OS version 5.0.x (as listed) or is one of the specific Nexus/FEX models, and SNMP is enabled and reachable by authenticated users.

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

Remediation

From vendor data

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Apply the Cisco patch for Bug ID CSCtr65682, which typically involves updating to a fixed NX-OS version. If immediate patching is not feasible, restrict SNMP access to trusted management networks and monitor memory usage closely.

Fix this in Nx Os Scoped from the published advisory

Consultation2.0 h
Implementation4.0 h
Testing2.0 h
Review / QA1.0 h

9.0 hours of engineering $1,600

Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

Scan for this in your stack

Free · runs locally

dbcve dependency scanner

Check whether your project pulls in CVE-2011-4023 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References

Primary sources

www.cisco.com
nvd.nist.govNVD record

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2011-4023 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2011-4023?

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

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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

At a glance

A fix existsA vendor remedy is published

Severity 7.8 High

Exploit likelihood EPSS, next 30 days 1.3%

Affects: Nx Os

Remediation

A high-priority fix

Fix this in Nx Os 9 hrs · Moderate

Typical engagement from $1,600

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2011-4023 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

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

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References