CVE-2026-2566
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 · uneditedA security vulnerability has been detected in Wavlink WL-NU516U1 up to 130/260. This affects the function sub_406194 of the file /cgi-bin/adm.cgi. Such manipulation of the argument firmware_url leads to stack-based buffer overflow. The attack can be launched remotely. The exploit has been disclosed publicly and may be used. 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 confidenceStack-based buffer overflow in Wavlink WL-NU516U1 routers (firmware up to 130/260) in the /cgi-bin/adm.cgi web interface. The vulnerable sub_406194 function fails to properly validate the firmware_url parameter length before copying it to a fixed-size stack buffer, allowing remote attackers to overwrite return addresses and execute arbitrary code.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:H/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 modelAccess the router admin interface or check the device label to confirm the exact model is Wavlink WL-NU516U1Affected if The device is not a Wavlink WL-NU516U1 router
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Check firmware versionLog into the router admin panel, typically at 192.168.1.1 or 192.168.10.1, and navigate to System Settings or Status to view the firmware version numberAffected if The firmware version is 130, 260, or any version up to and including those numbers (no patch version specified)
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Verify web interface accessibilityAttempt to access http://<router-ip>/cgi-bin/adm.cgi from a browser to confirm the web interface is runningAffected if The adm.cgi endpoint is reachable and responds to requests
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Check remote administration statusIn the router admin panel, locate the Remote Management or Administration settings and verify whether remote access to the web interface is enabledAffected if Remote administration is enabled, allowing the vulnerable endpoint to be accessed from outside the local network
A user is affected if they own a Wavlink WL-NU516U1 router running firmware version 130 or 260 (or any version up to those) with the adm.cgi web interface accessible, especially if remote administration is enabled.
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 dataSince the vendor has not responded to the disclosure, implement network-level filtering to restrict access to the adm.cgi interface, disable remote administration if not required, and consider replacing the device if no firmware update becomes available. If continued use is necessary, a source code patch adding proper bounds checking on the firmware_url parameter would be required.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-2566 — 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-2026-2566 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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- Version or environment caveats, and links to real fixes
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