dbcve.org
Nx OsOperating system · Cisco

CVE-2017-12335

MEDIUM · 6.3 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 →
65/100
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 the CLI of Cisco NX-OS System Software could allow an authenticated, local attacker to perform a command injection attack. The vulnerability is due to insufficient input validation of command arguments. An attacker could exploit this vulnerability by injecting crafted command arguments into a vulnerable CLI command and gain unauthorized access to the underlying operating system of the device. An exploit could allow the attacker to execute arbitrary commands at the user's privilege level. On products that support multiple virtual device contexts (VDCs), this vulnerability could allow an attacker to execute commands at the user's privilege level outside the user's environment. This vulnerability affects the following products running Cisco NX-OS System Software: Multilayer Director Switches, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 5000 Series Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, Unified Computing System Manager. Cisco Bug IDs: CSCvf14923, CSCvf14926, CSCvg04095.

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

A command injection vulnerability exists in the CLI of Cisco NX-OS System Software due to insufficient input validation of command arguments. An authenticated local attacker can inject crafted command arguments into vulnerable CLI commands to execute arbitrary commands at the user's privilege level, potentially gaining unauthorized access to the underlying operating system.

MitigationApply the relevant Cisco software updates for the specific product (CSCvf14923, CSCvf14926, CSCvg04095) to address the insufficient input validation in the CLI. No workarounds are mentioned; patching is required.

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:= 7.0\(0\)hsk\(0.357\)= 8.1\(0\)bd\(0.20\)= 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
Low
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.0/AV:L/AC:L/PR:L/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 checks

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

  1. Identify the Cisco product and version
    Log into the device CLI and run 'show version' to obtain the installed software version. For NX-OS, note the exact version string (e.g., 7.0(0)hsk(0.357), 8.1(0)bd(0.20), 8.1(1)). For Cisco UCS, run 'show version' in the UCS Manager or 'sysinfo' in the NX-OS mode.
    Affected if The installed version matches exactly 7.0(0)hsk(0.357), 8.1(0)bd(0.20), 8.1(1) on NX-OS, or 7.0(0)hsk(0.357) on Cisco Unified Computing System.
  2. Confirm CLI access is available
    Verify that command-line interface access is enabled and functional by attempting to access the device locally or via SSH/Telnet. Run a basic show command (e.g., 'show running-config' or 'show interface brief') to confirm CLI responsiveness.
    Affected if CLI access is available to authenticated users, as the vulnerability requires an authenticated local attacker to inject command arguments.
  3. Check user privilege levels and authentication method
    Run 'show users' to see currently logged-in users and their privilege levels. Run 'show privilege' to confirm your current privilege level. Review 'show aaa authentication' and 'show role' to understand the authentication and authorization configuration.
    Affected if Multiple users with varying privilege levels exist, or the device uses local authentication, as this increases the attack surface for an authenticated local attacker.
  4. Review recent CLI command logs
    Check for any suspicious CLI activity by reviewing 'show logging' output, particularly around command execution. Look for unexpected or malformed command arguments in the logs.
    Affected if Unexplained command executions or malformed arguments appear in the logs, which may indicate attempted or successful exploitation.

The environment is affected if the installed Cisco NX-OS version is exactly 7.0(0)hsk(0.357), 8.1(0)bd(0.20), or 8.1(1), or if Cisco Unified Computing System is at version 7.0(0)hsk(0.357), and the CLI is accessible to authenticated users.

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 the relevant Cisco software updates for the specific product (CSCvf14923, CSCvf14926, CSCvg04095) to address the insufficient input validation in the CLI. No workarounds are mentioned; patching is required.

Fix this in Nx Os Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2017-12335 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