CVE-2026-7720
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 weakness has been identified in Totolink WA300 5.2cu.7112_B20190227. The impacted element is the function setLanguageCfg of the file /cgi-bin/cstecgi.cgi of the component POST Request Handler. This manipulation of the argument langType causes command injection. Remote exploitation of the attack is possible. The exploit has been made available to the public and could be used for attacks.
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 command injection vulnerability exists in Totolink WA300 router firmware (5.2cu.7112_B20190227) in the setLanguageCfg function of /cgi-bin/cstecgi.cgi. The langType parameter in POST requests is not properly sanitized, allowing an attacker to inject arbitrary OS commands through the CGI binary.
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
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
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 firmware versionAccess the router's web administration interface and navigate to System Status or Firmware Upgrade page to view the current firmware version, or use the command 'cat /proc/version' or 'nvram get firmware_version' if you have telnet/ssh access to the device.Affected if The installed firmware version matches 5.2cu.7112_B20190227 or is earlier than this specific build.
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Confirm the router modelCheck the device label on the physical router or the web interface System Status page to confirm the model is Totolink WA300.Affected if The device is a Totolink WA300 router.
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Verify the CGI binary existsAttempt to access http://<router-ip>/cgi-bin/cstecgi.cgi via HTTP GET request. A valid response indicates the CGI binary is present and the endpoint is enabled.Affected if The CGI binary responds to requests, indicating the vulnerable endpoint is present.
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Check if the web management interface is exposedReview router firewall settings or network configuration to determine if the web interface (port 80/443) is accessible from untrusted networks or the WAN interface.Affected if The web management interface is reachable from untrusted networks (not limited to trusted IP addresses).
You are affected if you have a Totolink WA300 router running firmware version 5.2cu.7112_B20190227 or earlier, with the web interface and /cgi-bin/cstecgi.cgi endpoint accessible to untrusted networks.
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 dataRestrict network access to the router's web management interface to trusted IPs only. If available, apply vendor firmware updates; otherwise, disable the affected CGI endpoint or implement upstream input filtering.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-7720 — 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-2026-7720 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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