dbcve.org
Dir 816l FirmwareOperating system · Dlink

CVE-2025-13189

CRITICAL · 9.8 CVSS v3.1 Published 2025-11-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

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 · unedited
A vulnerability has been found in D-Link DIR-816L 2_06_b09_beta. This affects the function genacgi_main of the file gena.cgi. The manipulation of the argument SERVER_ID/HTTP_SID leads to stack-based buffer overflow. The attack is possible to be carried out remotely. The exploit has been disclosed to the public and may be used. This vulnerability only affects products that are no longer supported by the maintainer.

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 confidence

Stack-based buffer overflow in D-Link DIR-816L firmware's gena.cgi (genacgi_main function) via manipulated SERVER_ID/HTTP_SID arguments. The vulnerability is remotely exploitable without authentication (CVSS 9.8) and allows potential complete system compromise via remote code execution.

MitigationThis is an end-of-life product with no vendor patch available. Replace the device with a currently supported model. If replacement is not immediately feasible, isolate the device on a restricted network segment and disable remote management interfaces to reduce attack surface.

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
Dir 816l FirmwareOperating system
Affected:= 2.06.b09

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify firmware version
    Access the device's web management interface and navigate to the Status or System Information page to view the firmware version. Alternatively, check the firmware file name if you have access to the device's filesystem or backup configuration.
    Affected if The firmware version is exactly 2.06.b09 (this is the only affected version listed)
  2. Confirm gena.cgi is present and accessible
    Attempt to access the gena.cgi endpoint on the device's web interface (e.g., http://<device_ip>/gena.cgi). The vulnerability exists in the genacgi_main function of this CGI script.
    Affected if The gena.cgi script is present and responds to requests (this is the vulnerable component)
  3. Verify if the web management interface is exposed
    Check the device's network configuration to determine if the HTTP/HTTPS management interface is listening on WAN-facing interfaces or only on LAN. This can be done via the web UI under Advanced > Network or similar, or by attempting to access the device's IP from an external network.
    Affected if The web management interface is accessible from WAN (remote management enabled) - this makes the vulnerability remotely exploitable without authentication

You are affected if your D-Link DIR-816L runs firmware version 2.06.b09 AND the gena.cgi web interface is accessible (particularly if remote management is enabled, allowing unauthenticated remote exploitation).

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

This is an end-of-life product with no vendor patch available. Replace the device with a currently supported model. If replacement is not immediately feasible, isolate the device on a restricted network segment and disable remote management interfaces to reduce attack surface.

Recommended fix High confidence
  1. This vulnerability affects D-Link DIR-816L firmware 2.06.b09, which D-Link has explicitly stated is no longer supported.
  2. There is no vendor-provided patch or firmware upgrade available for this end-of-life product.
  3. The recommended remediation is to replace the affected D-Link DIR-816L device with a currently supported router model from D-Link or another vendor.
  4. If the device cannot be replaced immediately, consider implementing network segmentation to isolate the affected device and restrict remote access to it.
Caveat This product is end-of-life with no firmware updates; replacement is the only vendor-recommended remediation

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Dir 816l Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-13189 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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