CVE-2026-7717
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 vulnerability was determined in Totolink WA300 5.2cu.7112_B20190227. This issue affects the function UploadCustomModule of the file /cgi-bin/cstecgi.cgi of the component POST Request Handler. Executing a manipulation of the argument File can lead to buffer overflow. The attack can be launched remotely. The exploit has been publicly disclosed and may be utilized.
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 confidenceA buffer overflow vulnerability exists in the UploadCustomModule function of /cgi-bin/cstecgi.cgi on Totolink WA300 routers (firmware 5.2cu.7112_B20190227). The vulnerability is triggered via a manipulated File parameter in a POST request, allowing remote attackers to potentially execute arbitrary code due to improper bounds checking.
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
- 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 checksWork through these to decide whether this CVE applies to you.
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Identify the router modelAccess the router's web interface and check the device status page, or inspect the device label for the model number. Alternatively, check the HTTP Server header or SNMP sysDescr if accessible.Affected if The device is NOT a Totolink WA300 router (different models are not affected by this specific CVE).
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Check the firmware versionLog into the router web interface and navigate to the Status or System Information page to view the firmware version. If CLI access is available, use the 'ver' or 'show version' command.Affected if The firmware version matches 5.2cu.7112_B20190227 or is earlier (older versions in the same release line may also contain the flaw).
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Verify the web interface is reachableAttempt to access the router's IP address on port 80 or 443 using a web browser or curl command: curl -I http://[router-ip]/Affected if The web interface is accessible from untrusted networks (the vulnerability is exploitable via HTTP POST to the cgi-bin endpoint).
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Confirm the vulnerable CGI endpoint existsSend a benign request to the/cgi-bin/cstecgi.cgi endpoint to verify it responds. For example: curl -X POST http://[router-ip]/cgi-bin/cstecgi.cgi -d 'test=1'Affected if The /cgi-bin/cstecgi.cgi endpoint returns a response (indicating the UploadCustomModule function is present and potentially accessible).
The device is affected if it is a Totolink WA300 router running firmware version 5.2cu.7112_B20190227 or earlier, and the web interface with the cgi-bin/cstecgi.cgi endpoint is accessible from the network being assessed.
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 vendor firmware update if available; otherwise, restrict or disable remote access to the web interface and implement network segmentation to limit exposure to trusted users only.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-7717 — 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-2026-7717 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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