CVE-2011-4821
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 · uneditedDirectory traversal vulnerability in the TFTP server in D-Link DIR-601 Wireless N150 Home Router with firmware 1.02NA allows remote attackers to read arbitrary files via unspecified vectors.
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 · moderate confidenceA directory traversal vulnerability exists in the TFTP server of D-Link DIR-601 Wireless N150 Home Router firmware 1.02NA. The flaw allows remote attackers to traverse directory paths using '../' sequences in TFTP requests, enabling unauthorized read access to files outside the intended TFTP root directory. This is a classic path traversal input validation failure in the file retrieval logic.
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= 1.02naall versionsCVSS 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
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- None
- Availability
- None
AV:N/AC:L/Au:N/C:P/I:N/A:N
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 router modelAccess the router's web interface or check the device label to confirm the model is D-Link DIR-601Affected if The device is a D-Link DIR-601 router
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Check the firmware versionLog into the router web interface and navigate to the Status or Administration section to view the firmware versionAffected if The firmware version is 1.02na or any version prior to a patched release (the vulnerability affects all versions)
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Verify TFTP server is enabledAccess the router's web interface and check the TFTP server settings, typically found under Advanced or Port Forwarding settingsAffected if The TFTP server feature is enabled on the router
You are affected if you have a D-Link DIR-601 router with TFTP server enabled, regardless of firmware version, as the directory traversal flaw exists in the TFTP service.
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 firmware update from D-Link to remediate this vulnerability. If no update is available, disable the TFTP server service if not required, or implement network segmentation/firewall rules to restrict TFTP access to trusted sources only.
- 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-2011-4821 — 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-2011-4821 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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