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Tl Wr940n FirmwareOperating system · Tp Link

CVE-2022-24355

HIGH · 8.8 CVSS v3.1 Published 2022-02-18
Fix available
A fix is available. Upgrade to 211111 or later.
See remediation →
93/100
Remediation priority · Urgent
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
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of TP-Link TL-WR940N 3.20.1 Build 200316 Rel.34392n (5553) routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the parsing of file name extensions. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-13910.

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 confidence

Stack-based buffer overflow in TP-Link TL-WR940N router firmware (v3.20.1) allows remote attackers to execute arbitrary code as root via parsing file name extensions without authentication. The vulnerability stems from missing length validation on user-supplied data before copying into a fixed-size stack buffer, enabling overflow and code execution.

MitigationApply vendor firmware patch when available. Until then, restrict network access to the router's management interface, disable WAN management, and segment the device on an isolated network.

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
Tl Wr940n FirmwareOperating system
Affected:< 211111

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/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. Confirm device model is TP-Link TL-WR940N
    Access the router admin web interface (typically at 192.168.0.1 or 192.168.1.1) and navigate to Status or System menu to view the device model. Alternatively, check the device label on the router hardware itself.
    Affected if Device model is TP-Link TL-WR940N
  2. Check installed firmware version
    In the router admin web interface, go to Status or System > Firmware Version. Compare the version number displayed against the affected range (any version before 211111, including v3.20.1).
    Affected if Firmware version is less than 211111
  3. Verify remote management access settings
    In the router admin web interface, navigate to Security or Remote Management settings. Check if 'Remote Management' or 'WAN Management' is enabled, and note which IP addresses or interfaces are permitted access.
    Affected if Remote management is enabled and accessible from WAN interface (0.0.0.0 or broad range)
  4. Confirm vulnerability trigger condition
    The vulnerability triggers when the router parses file name extensions in HTTP requests. This is a passive condition - the flaw exists if the firmware version is vulnerable, regardless of current network activity.
    Affected if Firmware version is vulnerable (< 211111) and the router is network-accessible

A user is affected if they own a TP-Link TL-WR940N router running firmware version less than 211111, particularly if remote management is enabled on the WAN interface.

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 211111 or later
Fixed in 211111
Interim mitigation

Apply vendor firmware patch when available. Until then, restrict network access to the router's management interface, disable WAN management, and segment the device on an isolated network.

Recommended fix High confidence

TP-Link TL-WR940N firmware version 211111 or later

  1. 1. Visit the official TP-Link support website for the TL-WR940N router
  2. 2. Download the latest firmware version (211111 or later) for your hardware version
  3. 3. Access the router's web management interface by navigating to the router's IP address
  4. 4. Navigate to System Tools > Firmware Upgrade (or similar path)
  5. 5. Click the button to choose the downloaded firmware file
  6. 6. Wait for the upload and flashing process to complete - do not power off the router
  7. 7. After reboot, verify the firmware version has been updated to 211111 or later
Caveat Standard firmware update risks apply - power interruption during flashing could brick the device; backup configuration if possible

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

Fix this in Tl Wr940n Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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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-2022-24355 in production — separate from our analysis above.

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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