Nx OsOperating system · Cisco
CVE-2017-6650
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 Telnet CLI command of Cisco NX-OS System Software 7.1 through 7.3 running on Cisco Nexus Series Switches 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 the Telnet CLI command. An exploit could allow the attacker to read or write arbitrary files at the user's privilege level outside of the user's path. Cisco Bug IDs: CSCvb86771.
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 confidenceA command injection vulnerability exists in the Telnet CLI command of Cisco NX-OS versions 7.1-7.3 running on Nexus Series Switches. Due to insufficient input validation of command arguments, an authenticated local attacker can inject crafted arguments to read or write arbitrary files at the user's privilege level outside of the user's normal path.
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
= 7.1\(1\)n1\(1\)= 7.1\(2\)n1\(1\)= 7.1\(3\)n1\(1\)= 7.1\(3\)n1\(2\)= 7.1\(3\)n1\(2.1\)= 7.1\(3\)n1\(3.12\)= 7.1\(4\)n1\(1\)= 7.2\(0\)d1\(0.437\)= 7.2\(0\)n1\(1\)= 7.2\(0\)zz\(99.1\)= 7.2\(1\)n1\(1\)= 7.3\(0\)n1\(1\)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
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify NX-OS versionExecute 'show version' or 'show version | include NXOS' in the CLI to retrieve the installed NX-OS version stringAffected if The displayed version matches any of the following: 7.1(1)n1(1), 7.1(2)n1(1), 7.1(3)n1(1), 7.1(3)n1(2), 7.1(3)n1(2.1), 7.1(3)n1(3.12), 7.1(4)n1(1), 7.2(0)d1(0.437), 7.2(0)n1(1), 7.2(0)zz(99.1), 7.2(1)n1(1), 7.3(0)n1(1)
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Confirm Telnet service is enabledExecute 'show running-config | include telnet' or 'show telnet server' to check if the Telnet server is activeAffected if Telnet is enabled and running on the device
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Verify local authentication configurationExecute 'show aaa authentication login' and review local user accounts with 'show user-account' to confirm whether local authentication is configuredAffected if Local user authentication is configured, allowing authenticated attackers to access the Telnet CLI
You are affected if your device runs any of the listed NX-OS versions and has Telnet enabled with local authentication users present.
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 relevant Cisco patch or upgrade to a fixed NX-OS version. If Telnet is not required, disable it entirely. Restrict local administrative access to prevent unauthorized authenticated sessions.
Fix this in Nx Os
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-6650 — 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-2017-6650 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
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