CVE-2019-3421
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 · uneditedThe 7520V3V1.0.0B09P27 version, and all earlier versions of ZTE product ZX297520V3 are impacted by a Command Injection vulnerability. Unauthorized users can exploit this vulnerability to control the user terminal system.
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 confidenceCommand injection vulnerability in ZTE ZX297520V3 routers (versions 7520V3V1.0.0B09P27 and earlier) allows remote, unauthorized attackers to execute arbitrary system commands on the affected device by injecting malicious input, potentially gaining full control of the user terminal 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<= 7520v3v1.0.0b09p27CVSS 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
- Adjacent
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:A/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 the device modelAccess the router's web admin interface (typically at 192.168.1.1 or 192.168.0.1) or check the device label/marketing materials to confirm the model is ZTE ZX297520V3Affected if The device is a ZTE ZX297520V3 router
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Locate the firmware versionIn the router web interface, navigate to Status or System Settings section to view the firmware version. Alternatively, check via CLI if telnet/SSH access is available using commands like 'cat /proc/version' or 'sysinfo'Affected if The firmware version displayed cannot be determined or shows as unknown
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Compare version against affected rangeCompare your installed firmware version string to '7520V3V1.0.0B09P27' - any version that is earlier than or equal to this version is affectedAffected if The firmware version is 7520V3V1.0.0B09P27 or any earlier version (such as 7520V3V1.0.0B08, B07, etc.)
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Check network exposureDetermine if the router's web management interface or remote administration features are accessible from the internet (check port forwarding rules, firewall settings, or perform an external port scan on the router's public IP for ports 80, 443, 8080)Affected if The router management interface is exposed to untrusted networks (internet-facing)
You are affected if you have a ZTE ZX297520V3 router running firmware version 7520V3V1.0.0B09P27 or any earlier version, especially if the admin interface is network-accessible.
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 vendor-provided firmware patch from ZTE to address the command injection vulnerability, and restrict network exposure of affected devices until the update is applied.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-3421 — 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-2019-3421 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
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