CVE-2020-6881
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 · uneditedZTE E8810/E8820/E8822 series routers have an MQTT DoS vulnerability, which is caused by the failure of the device to verify the validity of abnormal messages. A remote attacker could connect to the MQTT server and send an MQTT exception message to the specified device, which will cause the device to deny service. This affects:<ZXHN E8810, ZXHN E8820, ZXHN E8822><E8810 V1.0.26, E8810 V2.0.1, E8820 V1.1.3L, E8820 V2.0.13, E8822 V2.0.13>
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 confidenceThe ZTE E8810/E8820/E8820 series routers contain a denial of service vulnerability in their MQTT server component. The device fails to properly validate or sanitize abnormal MQTT messages, allowing a remote attacker to send specially crafted MQTT packets that cause the MQTT service to crash and become unresponsive.
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= 1.0.26= 2.0.1= 1.1.3= 2.0.13= 2.0.13CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 device modelAccess the router admin interface or check the device label to confirm the exact model number (E8810, E8820, or E8822).Affected if The device is not one of the three affected models.
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Check firmware versionLog into the router admin panel (typically via web GUI at 192.168.1.1 or 192.168.0.1) and navigate to Status or System Info to view the firmware version. Alternatively, check via CLI if telnet/ssh access is available.Affected if The firmware version matches exactly: E8810 at 1.0.26 or 2.0.1; E8820 at 1.1.3 or 2.0.13; E8822 at 2.0.13.
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Verify MQTT service is enabledCheck the router admin interface under Services or Applications for MQTT configuration. If CLI access is available, run 'netstat -tulpn | grep 1883' or check for an MQTT daemon process.Affected if MQTT service is actively running on the device.
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Check MQTT port accessibilityFrom an external network host, run 'nc -zv <router_public_ip> 1883' or use nmap to scan port 1883. From inside the network, test access to the LAN IP on port 1883.Affected if Port 1883 is open and reachable from an untrusted network segment.
You are affected if you run a ZTE E8810/E8820/E8822 router on one of the specific firmware versions listed AND have the MQTT service enabled and 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 dataRestrict network access to the MQTT service (port 1883) via firewall rules or ACLs to prevent unauthorized external connections. Monitor for vendor firmware updates and apply when available. If MQTT is not required, disable the service.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-6881 — 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-2020-6881 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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- Version or environment caveats, and links to real fixes
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