dbcve.org
Nx OsOperating system · Cisco

CVE-2017-12331

MEDIUM · 6.7 CVSS v3.0 Published 2017-11-30
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
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
A vulnerability in Cisco NX-OS System Software could allow an authenticated, local attacker to bypass signature verification when loading a software patch. The vulnerability is due to insufficient NX-OS signature verification for software patches. An authenticated, local attacker could exploit this vulnerability to bypass signature verification and load a crafted, unsigned software patch on a targeted device. The attacker would need valid administrator credentials to perform this exploit. This vulnerability affects the following products running Cisco NX-OS System Software: Multilayer Director Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Unified Computing System Manager. Cisco Bug IDs: CSCvf16494, CSCvf23655.

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

This vulnerability in Cisco NX-OS allows an authenticated local attacker with administrator credentials to bypass signature verification when loading software patches, enabling the execution of crafted unsigned patches on affected devices including Nexus 7000/7700 Series Switches and Multilayer Director Switches.

MitigationApply Cisco-supplied patches for NX-OS when available and enforce strict access controls on administrator accounts to limit the attack surface.

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:= 8.1\(1\)
Unified Computing SystemApplication
Affected:= 7.0\(0\)hsk\(0.357\)

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
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

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 the device model
    Run 'show version' or 'show module' to confirm the hardware model. Look for Nexus 7000, Nexus 7700, or MDS (Multilayer Director Switch) in the output.
    Affected if The device is NOT a Nexus 7000/7700 series or MDS switch - if so, the device is not affected by this specific CVE.
  2. Check the installed NX-OS version
    Run 'show version' and locate the 'NX-OS' or 'system' version line. Compare it to the affected version 8.1(1).
    Affected if The NX-OS version is exactly 8.1(1) - only this specific version is listed as affected.
  3. Check the Cisco UCS version (if applicable)
    For Unified Computing System devices, run 'show version' and look for the version string containing 7.0(0)hsk(0.357).
    Affected if The UCS version is exactly 7.0(0)hsk(0.357) - only this specific version is listed as affected.
  4. Verify administrator access exists
    Run 'show running-config | include username' or 'show users' to confirm local administrator accounts are configured on the device.
    Affected if The vulnerability requires an authenticated attacker with administrator credentials - if no local admin accounts exist, the attack path is not present.
  5. Confirm patch loading capability
    Run 'show running-config | include boot' or 'show file systems' to verify the device allows loading and installation of software images or patches.
    Affected if The device permits loading of software patches from external sources - this is required for the bypass to be exploitable.

The device is affected only if it is a Nexus 7000/7700 series or MDS switch running exactly NX-OS 8.1(1) or UCS version 7.0(0)hsk(0.357), with local administrator accounts enabled and the ability to load software patches.

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 Cisco-supplied patches for NX-OS when available and enforce strict access controls on administrator accounts to limit the attack surface.

Fix this in Nx Os Scoped from the published advisory
  • Consultation8.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,680
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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-2017-12331 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