CVE-2021-21748
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 MF971R product has two stack-based buffer overflow vulnerabilities. An attacker could exploit the vulnerabilities to execute arbitrary code.
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 confidenceThe ZTE MF971R mobile hotspot contains two stack-based buffer overflow vulnerabilities allowing unauthenticated remote attackers to execute arbitrary code. With a CVSS 9.8 rating, this is a critical flaw likely exploitable over the network without user interaction, potentially giving attackers full device control.
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= v1.0.0b05= 1v1.0.0b06= 2v1.0.0b03= s2v1.0.0b03= sv1.0.0b05CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/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 device modelLocate the device label on the ZTE MF971R mobile hotspot and confirm the model number is MF971R. Alternatively, access the device web interface (typically at 192.168.0.1 or 192.168.1.1) and check the device status page for model information.Affected if Device is not a ZTE MF971R (not affected by this specific CVE)
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Check firmware versionAccess the device web interface and navigate to the firmware or device information page. Look for the firmware version string displayed (examples include v1.0.0b05, 1v1.0.0b06, 2v1.0.0b03, s2v1.0.0b03, sv1.0.0b05). Alternatively, use AT command interface via serial or USB modem mode with command 'AT+ZPDINFO?' to retrieve version info.Affected if Firmware version matches one of: v1.0.0b05, 1v1.0.0b06, 2v1.0.0b03, s2v1.0.0b03, or sv1.0.0b05
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Verify remote management exposureCheck the device web interface under Settings or Network sections for remote management, TR-069 (CWMP), or WAN access settings. Determine if the device management interface is accessible from the WAN (cellular) side or if port forwarding is enabled.Affected if Remote management or administrative web interface is exposed to WAN/cellular network
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Review for indicators of compromiseCheck the device web interface for unexpected DNS settings, unknown DHCP clients, or unauthorized port forwarding rules. Review connected device logs for unfamiliar MAC addresses. Monitor network traffic for connections to suspicious external IPs, especially on unusual ports.Affected if Unknown devices on network, unexpected DNS servers configured, or suspicious outbound connections detected
Device is affected if it is a ZTE MF971R with firmware version v1.0.0b05, 1v1.0.0b06, 2v1.0.0b03, s2v1.0.0b03, or sv1.0.0b05 and remote management is exposed to the cellular network.
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 vendor firmware updates when available; until then, restrict network exposure via firewalls, disable unnecessary services, and monitor for indicators of compromise.
- Consultation8.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-21748 — 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-2021-21748 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