Nx OsOperating system · Cisco
CVE-2017-12351
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 · uneditedA vulnerability in the guest shell feature of Cisco NX-OS System Software could allow an authenticated, local attacker to read and send packets outside the scope of the guest shell container. An attacker would need valid administrator credentials to perform this attack. The vulnerability is due to insufficient internal security measures in the guest shell feature. An attacker could exploit this vulnerability by sending or receiving packets on the device-internal network outside of the guest shell container, aka "Unauthorized Internal Interface Access." This vulnerability affects the following products running Cisco NX-OS System Software: Nexus 3000 Series Switches, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules. Cisco Bug IDs: CSCvf33038.
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 confidenceThe guest shell feature in Cisco NX-OS contains insufficient internal security measures that allow an authenticated local attacker with administrator credentials to send and receive packets on device-internal networks outside the scope of the guest shell container, enabling unauthorized internal interface access.
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
= 7.0\(3\)i7\(1\)= 8.1\(0\)bd\(0.20\)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
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L
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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Check NX-OS versionRun 'show version' on the Cisco NX-OS device and locate the installed software version string (typically displayed as 'NX-OS: Version X.X(X)X' or similar)Affected if The installed version equals 7.0(3)i7(1) or 8.1(0bd(0.20)
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Verify guest shell feature is enabledRun 'show guestshell' or 'show feature | include guestshell' to determine if the guest shell feature is active on the deviceAffected if Guest shell feature is enabled and the NX-OS version matches one of the affected versions listed in step 1
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Confirm administrator access contextDetermine whether the device has any local user accounts with administrator-level privileges configured, as the vulnerability requires authentication with administrator credentialsAffected if Local administrator accounts exist and the device meets the version and guest shell conditions from previous steps
The environment is affected if the device runs NX-OS version 7.0(3)i7(1) or 8.1(0bd(0.20), has the guest shell feature enabled, and contains local administrator accounts that could exploit the insufficient internal security measures in the guest shell container.
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 CSCvf33038 to address the insufficient internal security measures in the guest shell feature; contact Cisco for the specific fixed software version for affected Nexus 3000, Nexus 9000, and Nexus 9500 R-Series platforms.
Fix this in Nx Os
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-12351 — 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-2017-12351 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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