Nx OsOperating system · Cisco
CVE-2012-4076
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 NX-OS allows local users to gain privileges and execute arbitrary commands via shell metacharacters in a command that calls the system library function, aka Bug IDs CSCtf23559 and CSCtf27780.
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 confidenceCisco NX-OS contains a local privilege escalation vulnerability where authenticated local users can inject arbitrary commands via shell metacharacters in commands that call the system library function. This allows users to bypass their assigned role permissions and execute commands with elevated privileges.
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
all versionsCVSS 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
- Local
- Complexity
- Low
- Authentication
- Single
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:L/AC:L/Au:S/C:C/I:C/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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Confirm the device is running Cisco NX-OSExecute 'show version' and look for 'NX-OS' in the outputAffected if The device runs any version of Cisco NX-OS
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Identify local user accounts configured on the systemExecute 'show user account' or review the running configuration for 'username' entries under the 'user' namespaceAffected if Local user accounts exist (authenticated local users are required for this vulnerability to be exploitable)
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Review assigned role permissions for local usersExecute 'show role' and cross-reference with 'show user-account' to see which roles are assigned to local usersAffected if Users are assigned roles other than 'network-admin' (the vulnerability allows bypassing role restrictions)
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Check for shell access enabled on user accountsExamine user configurations for 'shell' or 'suppress-shell' settings using 'show user-account detail'Affected if Users have shell access or the ability to execute commands through the CLI that call system library functions
A Cisco NX-OS system with local user accounts present is affected, since all NX-OS versions contain this privilege escalation flaw that allows authenticated users to inject commands and bypass their assigned role permissions.
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 dataApply the Cisco patch for bug IDs CSCtf23559 and CSCtf27780, or upgrade to a Cisco NX-OS version that includes the fix. Restrict local user access to untrusted accounts until the patch is applied.
Fix this in Nx Os
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-4076 — 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-2012-4076 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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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.
- 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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