CVE-2025-9935
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 N600R 4.3.0cu.7866_B20220506. This vulnerability affects the function sub_4159F8 of the file /web_cste/cgi-bin/cstecgi.cgi. Executing manipulation can lead to command injection. The attack can be executed 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 · high confidenceA command injection vulnerability exists in the cstecgi.cgi binary on TOTOLINK N600R routers (firmware 4.3.0cu.7866_B20220506). The vulnerable function sub_4159F8 in /web_cste/cgi-bin/cstecgi.cgi does not properly sanitize user input, allowing remote attackers to execute arbitrary operating system commands via crafted HTTP requests.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 4.3.0cu.7866_b20220506CVSS 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 the device modelLog into the router admin panel or check the device label to confirm the model is TOTOLINK N600RAffected if The device is not a TOTOLINK N600R router - different models are not affected by this specific CVE
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Check the installed firmware versionNavigate to the router's admin interface (usually at 192.168.0.1 or 192.168.1.1), look for a Status or System Info page, and record the firmware version numberAffected if The firmware version is exactly 4.3.0cu.7866_B20220506 - only this specific version is listed as vulnerable
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Verify the web management interface is accessibleAttempt to access the router's CGI endpoint at /cgi-bin/cstecgi.cgi or /web_cste/cgi-bin/cstecgi.cgi over HTTP from the networkAffected if The web interface is exposed and the cstecgi.cgi binary responds to requests - this is the attack surface for command injection
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Inspect the cstecgi.cgi binary if accessibleIf you have shell access or can extract the firmware, examine the binary at /web_cste/cgi-bin/cstecgi.cgi for the vulnerable function sub_4159F8Affected if The binary exists and contains the vulnerable function that does not sanitize user input before passing it to system calls
You are affected if you have a TOTOLINK N600R router running firmware version 4.3.0cu.7866_B20220506 with the web management interface accessible to the network.
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 the vendor-supplied firmware update to the TOTOLINK N600R device. If no update is available, disable the web management interface from untrusted networks or implement network segmentation to restrict access.
- Consultation4.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-9935 — 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-2025-9935 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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