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I21 FirmwareOperating system · Tenda

CVE-2024-4495

HIGH · 8.8 CVSS v3.1 Published 2024-05-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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
A vulnerability was found in Tenda i21 1.0.0.14(4656) and classified as critical. Affected by this issue is the function formWifiMacFilterGet. The manipulation of the argument index leads to stack-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-263084. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.

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

A stack-based buffer overflow vulnerability exists in the formWifiMacFilterGet function of Tenda i21 firmware version 1.0.0.14(4656). The vulnerability is triggered through manipulation of the 'index' argument, allowing an attacker to overflow a stack-based buffer. This can be exploited remotely with high complexity, potentially enabling remote code execution.

MitigationSince the vendor is unresponsive, immediate mitigations include network segmentation to limit exposure, disabling the WiFi MAC filter function if possible, and considering device replacement if no firmware update becomes available.

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
I21 FirmwareOperating system
Affected:= 1.0.0.14\(4656\)

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/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 checks

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

  1. Identify Tenda i21 device on your network
    Locate the device model number (i21) through network scanning, device inventory, or physical inspection of the hardware. Confirm this is a Tenda i21 access point or range extender.
    Affected if The device is not a Tenda i21 model - different models are not affected by this specific CVE.
  2. Check installed firmware version
    Access the device web interface or use the Tenda administration console to view the firmware version. The web UI typically shows firmware version in System Status or Device Info. Alternatively, check via CLI if telnet/ssh is enabled.
    Affected if Firmware version is exactly 1.0.0.14(4656) - this is the sole affected version listed in the CVE.
  3. Verify WiFi MAC filter function is accessible
    Log into the Tenda i21 admin interface and navigate to Wireless Settings or WiFi Security settings. Look for MAC filter configuration options (often labeled as MAC Filtering, Wireless MAC Filter, or Access Control).
    Affected if The MAC filter feature is present and can be configured - the vulnerability exists in the formWifiMacFilterGet function, indicating the MAC filter feature is implemented.
  4. Check for abnormal device behavior or crashes
    Monitor device stability and look for unexpected reboots, hangs, or crashes. Review any available system logs or status pages for error messages related to wireless functions.
    Affected if Device exhibits unexplained crashes or reboots, particularly when MAC filter settings are accessed or modified - this may indicate exploitation attempts.

You are affected only if you have a Tenda i21 device running firmware version 1.0.0.14(4656) with the WiFi MAC filter feature enabled and accessible.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Since the vendor is unresponsive, immediate mitigations include network segmentation to limit exposure, disabling the WiFi MAC filter function if possible, and considering device replacement if no firmware update becomes available.

Fix this in I21 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2024-4495 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
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