CVE-2022-43636
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 · uneditedThis vulnerability allows network-adjacent attackers to bypass authentication on affected installations of TP-Link TL-WR940N 6_211111 3.20.1(US) routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the httpd service, which listens on TCP port 80 by default. The issue results from the lack of sufficient randomness in the sequnce numbers used for session managment. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-18334.
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 TP-Link TL-WR940N router (firmware 3.20.1) has an authentication bypass vulnerability in its httpd web service (TCP port 80). The flaw stems from insufficient randomness in session sequence numbers, allowing attackers to predict or forge session identifiers and gain unauthorized administrative access without credentials.
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= 6_211111_3.20.1CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify router modelLog into the router admin panel or check the device label to confirm the model is TP-Link TL-WR940NAffected if The device is not a TL-WR940N model
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Check firmware versionAccess router admin panel (usually at 192.168.0.1) and navigate to Status or System Tools > Firmware Upgrade to view the installed versionAffected if Firmware version is 3.20.1 (specifically 6_211111_3.20.1)
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Verify httpd service is activeConfirm the router web management interface is reachable on TCP port 80 by accessing the router IP in a browserAffected if The httpd web service is running and accessible on port 80
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Check remote management settingsIn router admin panel, look for 'Remote Management' or 'Web Management' settings under Advanced or Security tabs to see if remote access is enabledAffected if Remote management is enabled, exposing the httpd service to network accessible attacks
If the device is a TP-Link TL-WR940N running firmware 3.20.1 with the httpd web service accessible on port 80, the environment is affected by this authentication bypass vulnerability.
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 the vendor-supplied firmware update when available; in the interim, restrict network access to the router's management interface and monitor for unauthorized access attempts.
- Consultation4.0 h
- Implementation8.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,880.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-43636 — 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-2022-43636 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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- 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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