dbcve.org
Mex01 FirmwareOperating system · Netu

CVE-2021-26621

CRITICAL · 9.8 CVSS v3.1 Published 2022-03-25
Fix available
A fix is available. Upgrade to 1.9.18 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
An Buffer Overflow vulnerability leading to remote code execution was discovered in MEX01. Remote attackers can use this vulnerability by using the property that the target program copies parameter values to memory through the strcpy() function.

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 confidence

Buffer overflow vulnerability in MEX01 where the strcpy() function copies parameter values to memory without bounds checking, allowing remote attackers to overflow buffers and achieve remote code execution.

MitigationReplace all strcpy() calls with bounds-safe alternatives (strncpy, strlcpy, or memcpy with explicit length) and implement input validation before string copy operations.

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
Mex01 FirmwareOperating system
Affected:< 1.9.18

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
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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Netu Mex01 device
    Locate the device or firmware and confirm it is the Netu Mex01 product line. Check device documentation, label, or firmware metadata for the product name.
    Affected if The device or firmware is not Netu Mex01, then this CVE does not apply.
  2. Check the installed firmware version
    Access the device management interface, firmware file metadata, or use a command such as 'version', 'fw_info', or similar firmware query command to retrieve the current firmware version number.
    Affected if The firmware version is less than 1.9.18 (for example, 1.9.17, 1.9.10, etc.), indicating the device is running a vulnerable version.
  3. Determine if remote management or network parameters are exposed
    Inspect the device network configuration and check whether remote management interfaces, API endpoints, or parameter input endpoints are accessible from the network. Look for web interfaces, APIs, or services that accept external parameter input.
    Affected if Remote management or parameter input interfaces are exposed to untrusted networks, making the strcpy() buffer overflow exploitable by remote attackers.
  4. Verify the strcpy-based parameter handling is in use
    If possible, analyze the firmware binary or configuration to confirm the vulnerable strcpy() code path handles externally-supplied parameters. This may require firmware reverse engineering or checking if the specific feature that uses strcpy for parameter copying is enabled.
    Affected if The specific feature that uses unbounded strcpy() to copy parameter values to memory is active and processing external input.

The environment is affected if the Netu Mex01 firmware version is below 1.9.18 AND the device exposes network-accessible interfaces that accept parameters processed by the vulnerable strcpy() code path.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to 1.9.18 or later
Fixed in 1.9.18
Interim mitigation

Replace all strcpy() calls with bounds-safe alternatives (strncpy, strlcpy, or memcpy with explicit length) and implement input validation before string copy operations.

Recommended fix High confidence

MEX01 Firmware 1.9.18

  1. Identify the MEX01 device or system running the affected firmware
  2. Check the current firmware version to confirm it is below 1.9.18
  3. Obtain firmware version 1.9.18 or later from the official vendor source (refer to vendor documentation for download location)
  4. Follow the vendor's standard firmware update procedure to apply the patched firmware version 1.9.18
  5. After update, verify the firmware version is 1.9.18 or higher and confirm normal device operation

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Mex01 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-26621 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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