CVE-2023-51631
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 SetUsersSettings 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-21675.
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 confidenceD-Link DIR-X3260 routers contain a stack-based buffer overflow vulnerability in the prog.cgi binary that handles HNAP requests to the lighttpd webserver. The flaw results from insufficient validation of user-supplied string data before copying to a fixed-size stack-based buffer. Successful exploitation requires authentication but allows arbitrary code execution 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:3.0/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 device modelAccess the router's web interface or check the device label/marketing to confirm the model is D-Link DIR-X3260Affected if The device is not a D-Link DIR-X3260 router - this vulnerability only affects that specific model
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Check installed firmware versionLog into the router web interface and navigate to Status or Management section to view the firmware version, or use a command like `cat /proc/version` or check the kernel banner if SSH/telnet access is availableAffected if Firmware version is 1.04b01 or higher - versions below 1.04b01 are affected
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Verify lighttpd webserver is runningCheck if the lighttpd web service is active on the device - on the router, this is typically running on ports 80 (HTTP) and 443 (HTTPS)Affected if The lighttpd service is not running - the prog.cgi binary that handles HNAP requests is only accessible when the webserver is active
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Confirm web management interface accessibilityAttempt to access the router's web interface via HTTP port 80 or HTTPS port 443 from the network segment where the router is deployedAffected if The web management interface is exposed and accessible - exploitation requires sending authenticated HNAP requests to prog.cgi through this interface
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Check if remote administration is enabledIn the router web interface, navigate to Management or Access Control settings to determine if remote management (WAN access) is enabled, which would allow exploitation from outside the local networkAffected if Remote administration is enabled on WAN interface - while exploitation requires authentication and can occur from LAN, remote access increases exposure
The environment is affected if the device is a D-Link DIR-X3260 running firmware version below 1.04b01, the lighttpd webserver is active, and the web management interface is accessible to an attacker who can obtain valid credentials.
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
Restrict access to the router's web management interface (ports 80/443), disable remote administration if enabled, and apply any available firmware updates from D-Link. Network segmentation can limit exposure to adjacent attackers.
Firmware version 1.04b01
- Navigate to D-Link's support website (support.dlink.com) and locate the DIR-X3260 product page
- Download the firmware version 1.04b01 or later from the firmware downloads section
- Access the router's web management interface by entering the router's IP address in a web browser
- Log in with administrator credentials
- Navigate to the Administration or Settings section and locate the Firmware Upgrade option
- Upload the downloaded firmware file and initiate the upgrade
- Wait for the upgrade to complete and the router to reboot
- Verify the firmware version has been updated to 1.04b01 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-51631 — 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-2023-51631 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
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