CVE-2025-4849
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 found in TOTOLINK N300RH 6.1c.1390_B20191101. It has been rated as critical. Affected by this issue is the function CloudACMunualUpdateUserdata of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument url leads to command injection. The attack may be launched remotely. The exploit has been disclosed to the 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 confidenceA command injection vulnerability exists in the TOTOLINK N300RH router firmware (version 6.1c.1390_B20191101). The vulnerable function CloudACMunualUpdateUserdata in /cgi-bin/cstecgi.cgi accepts user input through the 'url' parameter without proper sanitization, allowing an unauthenticated remote attacker to execute arbitrary OS commands.
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= 6.1c.1390_b20191101CVSS 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 modelCheck the router label or web interface for the exact model number (N300RH)Affected if Device is a TOTOLINK N300RH router
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Check firmware versionAccess router web interface or check system info page for firmware version. The affected version is exactly 6.1c.1390_b20191101Affected if Firmware version is 6.1c.1390_b20191101 exactly
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Verify CGI endpoint accessibilityAttempt to access or check firewall rules for /cgi-bin/cstecgi.cgi endpoint on the routerAffected if The CGI endpoint is reachable from untrusted network segments
If the device is a TOTOLINK N300RH running firmware version 6.1c.1390_b20191101 and the web interface is network-accessible, the environment is affected by this command injection vulnerability.
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 dataImmediately restrict network access to the router's web interface from untrusted networks. Check TOTOLINK for available firmware updates and apply them. If no patch is available, consider replacing the device or implementing strict firewall rules to block external access to the cgi-bin endpoints.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-4849 — 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-2025-4849 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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