CVE-2026-7548
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 detected in Totolink NR1800X 9.1.0u.6279_B20210910. This affects the function sub_41A68C of the file /cgi-bin/cstecgi.cgi. Performing a manipulation of the argument setUssd results in command injection. The attack is possible to be carried out remotely. The exploit is now public and may be used.
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 confidenceCommand injection vulnerability in Totolink NR1800X router firmware (v9.1.0u.6279_B20210910). The /cgi-bin/cstecgi.cgi CGI binary does not sanitize user input passed via the setUssd parameter to function sub_41A68C, allowing an attacker to inject and execute arbitrary OS commands on the device remotely.
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.
-
Identify router modelCheck the device label or access the router admin interface to confirm the model is Totolink NR1800XAffected if Router model is NR1800X and firmware version is v9.1.0u.6279_B20210910 or earlier unpatched versions
-
Check firmware versionAccess router web UI (typically 192.168.1.1), navigate to System Status or Firmware Upgrade page to view the installed firmware version stringAffected if Installed firmware version matches v9.1.0u.6279_B20210910 or is an earlier version before vendor patch
-
Verify CGI binary existsAttempt to access the CGI endpoint via HTTP/HTTPS: http://[router-ip]/cgi-bin/cstecgi.cgiAffected if The /cgi-bin/cstecgi.cgi endpoint responds (indicates the web interface is active)
-
Check WAN accessibility of web interfaceTest if the router's web interface is reachable from an external IP by attempting HTTP connections to the router's WAN IP on port 80/443Affected if Router web interface (ports 80/443) is exposed to WAN/internet and vulnerable CGI is accessible externally
-
Confirm setUssd parameter handling existsReview firmware binary or test sending a request with setUssd parameter to /cgi-bin/cstecgi.cgi - if the device processes this parameter, the function sub_41A68C exists in the firmwareAffected if The setUssd parameter is accepted and processed by the CGI binary (indicates vulnerable code path is present)
User is affected if they have a Totolink NR1800X router running firmware v9.1.0u.6279_B20210910 (or earlier) with the web interface accessible (especially from WAN), enabling remote command injection via the setUssd parameter in /cgi-bin/cstecgi.cgi.
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 patch if available; otherwise, restrict network access to the router's web interface (disable WAN access, use firewall rules) to prevent remote exploitation of this command injection flaw.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 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 $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-7548 — 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-2026-7548 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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