Enterprise Nfv Infrastructure SoftwareApplication · Cisco
CVE-2021-1421
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 Cisco Enterprise NFV Infrastructure Software (NFVIS) could allow an authenticated, local attacker to perform a command injection attack on an affected device. The vulnerability is due to insufficient validation of user-supplied input to a configuration command. An attacker could exploit this vulnerability by including malicious input during the execution of this command. A successful exploit could allow a non-privileged attacker authenticated in the restricted CLI to execute arbitrary commands on the underlying operating system (OS) with root privileges.
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 confidenceA command injection vulnerability in Cisco Enterprise NFV Infrastructure Software (NFVIS) allows authenticated users in the restricted CLI to inject malicious commands through a configuration command due to insufficient input validation, enabling a non-privileged attacker to execute arbitrary commands with root privileges on the underlying operating system.
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
Enterprise Nfv Infrastructure SoftwareApplication
< 4.5.1CVSS 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:3.1/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 NFVIS installation and versionAccess the NFVIS CLI or administrative interface and run the command to display the software version (typically 'show version' or similar NFVIS-specific command). Compare the displayed version number against the affected range of versions prior to 4.5.1.Affected if The installed version is any release prior to 4.5.1 (for example, 4.5.0, 4.4.x, or earlier).
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Verify restricted CLI access is configuredExamine the NFVIS configuration to determine if restricted CLI user accounts have been created. Check for user accounts assigned to the restricted shell or limited CLI permission level.Affected if Restricted CLI user accounts exist and are active on the system.
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Check for unauthorized changes to system configurationReview NFVIS configuration files and running configuration for unexpected entries, particularly in areas where configuration commands are applied (such as boot variables, scripts, or custom configurations).Affected if Configuration contains unexpected or malicious commands, scripts, or modified settings not authored by legitimate administrators.
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Audit system logs for suspicious CLI activityReview NFVIS and underlying OS logs for command patterns that indicate exploitation, such as unusual command sequences, spawning of shells, or execution of unexpected system utilities from the restricted CLI context.Affected if Logs contain evidence of command injection attempts or unexpected command execution from restricted CLI sessions.
The environment is affected if NFVIS version is prior to 4.5.1 and restricted CLI access is enabled or has been used, regardless of whether exploitation is detected in logs.
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 data4.5.1
Apply the vendor-provided patch from Cisco. Until patched, strictly limit CLI access to trusted users only and implement monitoring for suspicious command patterns in logs.
Fix this in Enterprise Nfv Infrastructure Software
Scoped from the published advisory
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA6.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1421 — 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-2021-1421 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
- No spam, self-promotion, credentials, or personal data