CVE-2021-40655
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 · uneditedAn informtion disclosure issue exists in D-LINK-DIR-605 B2 Firmware Version : 2.01MT. An attacker can obtain a user name and password by forging a post request to the / getcfg.php page
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 confidenceThe D-Link DIR-605 B2 router firmware version 2.01MT contains an unauthenticated information disclosure vulnerability in the /getcfg.php page. By sending a forged POST request to this endpoint, an attacker can obtain plaintext user credentials (username and password) without any authentication, allowing full administrative access to the device.
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= 2.01mtCVSS 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
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 device modelAccess the device admin interface or check the device label. Look for D-Link DIR-605L B2 model marking.Affected if Device model is not D-Link DIR-605L B2, then not affected.
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Check firmware versionLog into the router admin panel and navigate to the Status or Maintenance section to view firmware version, or use an HTTP GET request to / or /Status.md and parse the HTML for version strings.Affected if Firmware version is not 2.01MT, then not affected. Only version 2.01MT is listed as vulnerable.
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Verify /getcfg.php endpoint is presentSend an HTTP POST request to http://[device-ip]/getcfg.php with a minimal payload such as a POSTDATA parameter. Use curl: curl -X POST -d 'POSTDATA=<?xml version="1.0"?><postxml></postxml>' http://[device-ip]/getcfg.phpAffected if The endpoint responds with configuration data containing SERVICES or ACCOUNT settings, indicating the vulnerability is present and exploitable.
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Confirm network exposureDetermine if the router management interface (HTTP port 80) is accessible from untrusted networks such as the internet or guest VLANs. Check firewall rules and port forwarding configurations.Affected if The /getcfg.php endpoint is reachable from unauthenticated network locations, enabling remote exploitation.
You are affected if you have a D-Link DIR-605L B2 device running firmware version 2.01MT with the /getcfg.php endpoint accessible from your 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 patch if available; otherwise replace the end-of-life device and rotate all credentials. Restrict administrative interface access to trusted networks only.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-40655 — 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-2021-40655 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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