CVE-2023-51620
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 · uneditedD-Link DIR-X3260 prog.cgi SetIPv6PppoeSettings Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of D-Link DIR-X3260 routers. Authentication is required to exploit this vulnerability. The specific flaw exists within the prog.cgi binary, which handles HNAP requests made to the lighttpd webserver listening on TCP ports 80 and 443. The issue results from the lack of proper validation of a user-supplied string before copying it to a fixed-size stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-21669.
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 confidenceStack-based buffer overflow in prog.cgi binary of D-Link DIR-X3260 routers handling HNAP requests on lighttpd webserver (ports 80/443). The SetIPv6PppoeSettings function fails to validate user-supplied input before copying to a fixed-size stack buffer, allowing authenticated network-adjacent attackers to execute arbitrary code with root privileges.
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< 1.04b01CVSS 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
- Adjacent
- Complexity
- Low
- Privileges
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:H/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 modelCheck the device label or access the router admin interface and look for the model number in the status or system information pageAffected if The device is NOT a D-Link DIR-X3260 router (if it's a different model, this specific CVE does not apply)
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Check the installed firmware versionAccess the router admin interface (typically at 192.168.0.1), navigate to the status or firmware upgrade page, and record the firmware version stringAffected if The firmware version is lower than 1.04b01 (for example, 1.03 or earlier)
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Verify the webserver is accessibleAttempt to access http://router-ip/ and https://router-ip/ on ports 80 and 443 respectively using a web browser or curl commandAffected if The lighttpd webserver responds on ports 80/443 (this confirms the attack surface exists)
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Confirm HNAP endpoint is availableSend a SOAP request to the HNAP location (typically /HNAP1/ or check for HNAP-related headers/paths in the web interface)Affected if The HNAP endpoint is reachable and responds to requests (this is the vulnerable service)
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Check for authenticated accessAttempt to log into the router admin interface with valid credentials or verify if default credentials are still in useAffected if You have valid admin credentials to access the router (authentication is required for the exploit)
Your device is affected if it is a D-Link DIR-X3260 router running firmware version lower than 1.04b01, with the lighttpd webserver and HNAP interface accessible to an authenticated network-adjacent attacker.
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.
dbcve · scoped1.04b01
Apply vendor firmware patch when available; until then, restrict access to router management interface to trusted networks only and disable HNAP if possible.
D-Link DIR-X3260 Firmware version 1.04b01 or later
- 1. Visit the official D-Link support page at support.dlink.com
- 2. Search for DIR-X3260 router firmware downloads
- 3. Download firmware version 1.04b01 or later
- 4. Access the router web interface at http://192.168.0.1 (or the router's default IP)
- 5. Navigate to the Administration or System settings section
- 6. Locate the Firmware Upgrade option
- 7. Upload the downloaded firmware file and apply the update
- 8. Wait for the router to reboot and verify the update was successful
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,152.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-51620 — 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-2023-51620 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data