CVE-2026-6112
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 A7100RU 7.4cu.2313_b20191024. Affected is the function setRadvdCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. This manipulation of the argument maxRtrAdvInterval causes os command injection. The attack can be initiated remotely. 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 · high confidenceA critical OS command injection vulnerability exists in the Totolink A7100RU router firmware (v7.4cu.2313_b20191024). The vulnerability resides in the CGI handler (/cgi-bin/cstecgi.cgi) within the setRadvdCfg function, where the maxRtrAdvInterval parameter is not properly sanitized before being passed to system shell execution, allowing remote attackers to execute arbitrary commands.
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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Confirm device model is Totolink A7100RULog into the router web interface or check the device label/sticker to verify the exact model numberAffected if The device is not a Totolink A7100RU router, then this specific CVE does not apply
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Identify installed firmware versionAccess the router admin panel (usually at 192.168.0.1 or 192.168.1.1), navigate to System or Firmware status section to view the current firmware versionAffected if The running firmware version matches v7.4cu.2313_b20191024 or is an earlier version from the same release line
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Verify radvd service is enabledCheck the router administration interface for RADVD or Router Advertisement Daemon configuration settings; this service must be active for the vulnerable setRadvdCfg function to be exploitableAffected if The radvd service is enabled and accessible through the web interface CGI handler
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Confirm CGI endpoint is network-accessibleAttempt to access http://<router-ip>/cgi-bin/cstecgi.cgi from an internal network host; the endpoint should respond (even if with an error) to indicate it is reachableAffected if The /cgi-bin/cstecgi.cgi endpoint is reachable from the network and accepts requests
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Check external network exposure of router admin interfaceUse an external host or online port scanner to verify whether the router HTTP ports (80/443) are exposed to the internet; also check NAT/firewall rules that might forward admin access externallyAffected if The router admin interface or CGI endpoint is directly accessible from the internet without VPN or VLAN isolation
You are affected if you are running Totolink A7100RU firmware v7.4cu.2313_b20191024 (or earlier) with the radvd service enabled and the CGI interface accessible from a network where an attacker could send malicious maxRtrAdvInterval parameters.
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 dataUpgrade router firmware to a patched version if available; otherwise, disable the radvd service or restrict network access to the CGI interface via firewall rules to mitigate remote exploitation.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-6112 — 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-2026-6112 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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