CVE-2026-7823
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 flaw has been discovered in Totolink A8000RU 7.1cu.643_b20200521. Affected is the function setAppFilterCfg of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument enable results in os command injection. The attack may be launched remotely. The exploit has been released to the public and may 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 · high confidenceOS command injection vulnerability in Totolink A8000RU router firmware 7.1cu.643_b20200521. The web interface CGI script /cgi-bin/cstecgi.cgi does not properly sanitize input to the 'enable' parameter in the setAppFilterCfg function, allowing arbitrary command execution with root privileges.
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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/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 device model and firmware versionAccess the router's web administration interface and navigate to System Status or Firmware version page. Alternatively, check the label on the device or use the command 'cat /proc/version' or 'nvram get firmver' if you have telnet/ssh access.Affected if The device is a Totolink A8000RU running firmware version 7.1cu.643_b20200521.
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Confirm vulnerable CGI script presenceAccess the router's web interface and attempt to reach /cgi-bin/cstecgi.cgi via HTTP GET request, or check the filesystem via telnet/ssh if available using 'ls -la /www/cgi-bin/cstecgi.cgi'.Affected if The file /cgi-bin/cstecgi.cgi exists on the device.
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Determine if web interface is network accessibleCheck router administration settings to see if Remote Management/Remote Administration is enabled. From an external host, attempt to reach the router's IP on ports 80/443 using 'curl http://<router-ip>/' or 'nmap -p 80,443 <router-ip>'.Affected if The web interface is accessible from untrusted networks, or Remote Administration is enabled allowing external access.
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Inspect for indicators of compromiseReview router logs for suspicious requests to /cgi-bin/cstecgi.cgi, especially with unusual 'enable' parameter values. Check for unexpected new admin accounts, changed DNS settings, or unknown processes using 'ps' command via telnet/ssh.Affected if Log entries show requests to the CGI with command-like strings in the 'enable' parameter, or unauthorized configuration changes are detected.
A defender is affected if they have a Totolink A8000RU router running firmware 7.1cu.643_b20200521 with the web interface accessible to untrusted networks, and the vulnerable CGI script is present.
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 when available; until then, restrict network access to the router's web interface, disable remote administration if enabled, and monitor for indicators of compromise.
- Consultation3.0 h
- Implementation1.0 h
- Testing6.0 h
- Review / QA3.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-7823 — 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-2026-7823 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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