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Dir 816 FirmwareOperating system · Dlink

CVE-2026-4180

CRITICAL · 9.8 CVSS v3.1 Published 2026-03-16
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 was identified in D-Link DIR-816 1.10CNB05. The impacted element is an unknown function of the file redirect.asp of the component goahead. The manipulation of the argument token_id leads to improper access controls. The attack may be initiated remotely. The exploit is publicly available and might 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 · moderate confidence

D-Link DIR-816 1.10CNB05 router contains an improper access control vulnerability in the goahead web server component's redirect.asp file. The token_id parameter can be manipulated to bypass authentication and access restricted functionality. This is a critical remote code execution/path traversal enabler due to complete authentication bypass.

MitigationSince D-Link has discontinued support for this product, replace the affected device with a currently supported model. If immediate replacement is not feasible, disable remote web management, restrict administrative interface to local-only access via firewall rules, and segment the device on an isolated VLAN.

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 816 FirmwareOperating system
Affected:= 1.10cnb05

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 the firmware version of your D-Link DIR-816
    Log into the router web interface and navigate to Status or System Settings to view the firmware version. Alternatively, check the kernel boot messages or the /proc/version file if you have telnet/ssh access.
    Affected if The firmware version displayed is 1.10CNB05 exactly.
  2. Verify the goahead web server component is present
    Check if the router web interface is accessible by navigating to the device's IP address in a browser. The vulnerability exists in the goahead web server's redirect.asp file.
    Affected if The router web interface loads successfully, indicating the goahead web server is running.
  3. Confirm the redirect.asp endpoint exists
    Attempt to access the redirect.asp file via HTTP (for example: http://<router-ip>/redirect.asp). The presence of this file confirms the vulnerable component is installed.
    Affected if The redirect.asp file is found and responds to requests.
  4. Determine if remote web management is enabled
    In the router web interface, check the Access Control or Management settings to see if remote (WAN) web management is permitted. This setting controls whether the web interface is accessible from outside the local network.
    Affected if Remote web management is enabled, allowing the vulnerable web server to be reached from external networks.

You are affected if your D-Link DIR-816 runs firmware version 1.10CNB05 and the router web interface (containing the vulnerable redirect.asp file) is accessible, especially if remote web management is enabled.

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

Since D-Link has discontinued support for this product, replace the affected device with a currently supported model. If immediate replacement is not feasible, disable remote web management, restrict administrative interface to local-only access via firewall rules, and segment the device on an isolated VLAN.

Recommended fix High confidence
  1. This vulnerability affects D-Link DIR-816 firmware 1.10CNB05, which D-Link has explicitly stated is no longer supported.
  2. Replace the affected D-Link DIR-816 device with a currently supported router from D-Link or another vendor.
  3. If immediate replacement is not possible, isolate the affected device on a separate VLAN or behind a firewall with strict access control rules to limit exposure.
  4. Disable remote management interfaces (web UI) from the WAN side if not absolutely required.
  5. Monitor the network for any suspicious activity targeting the affected device.
  6. Consider deploying an intrusion detection system to alert on potential exploitation attempts.

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

Fix this in Dir 816 Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2026-4180 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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