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Dir 859 FirmwareOperating system · Dlink

CVE-2023-36092

CRITICAL · 9.8 CVSS v3.1 Published 2023-07-31
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
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
Authentication Bypass vulnerability in D-Link DIR-859 FW105b03 allows remote attackers to gain escalated privileges via via phpcgi_main. NOTE: 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

Authentication bypass vulnerability in D-Link DIR-859 router firmware FW105b03 allows remote attackers to escalate privileges via the phpcgi_main component. The vulnerability enables unauthenticated attackers to bypass authentication mechanisms and gain administrative access to the affected device.

MitigationSince this is an end-of-life product with no vendor patch available, replace the affected device with a supported model. If immediate replacement is not feasible, isolate the device behind a firewall and restrict all external access to minimize exposure.

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 859 FirmwareOperating system
Affected:= 1.05b03

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. Verify router model is D-Link DIR-859
    Check the device label on the router or access the admin interface and look for the model number in the status or system information page
    Affected if The device is a D-Link DIR-859 router
  2. Check firmware version is 1.05b03
    Access the router admin interface, navigate to the firmware or status page, and locate the firmware version string. Alternatively, check the version via telnet/SSH if enabled or by examining the firmware file if you have local access
    Affected if The firmware version displayed is exactly 1.05b03
  3. Confirm phpcgi_main component is accessible
    Attempt to access the router web interface on the typical HTTP/HTTPS ports (80/443). The phpcgi_main component handles PHP CGI requests for the web management interface. If the web interface responds, the component is present
    Affected if The router web management interface is reachable and responds to requests, indicating the phpcgi_main component is active
  4. Verify authentication bypass is present
    Attempt to access restricted administrative pages or APIs without providing credentials. The vulnerability allows bypassing the login check in the phpcgi_main component. Try accessing protected URLs directly without session authentication
    Affected if Administrative pages or sensitive router functions are accessible without providing valid credentials, confirming the authentication bypass is exploitable

The device is affected if it is a D-Link DIR-859 router running firmware version 1.05b03 and the web management interface (phpcgi_main component) is accessible.

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 this is an end-of-life product with no vendor patch available, replace the affected device with a supported model. If immediate replacement is not feasible, isolate the device behind a firewall and restrict all external access to minimize exposure.

Recommended fix High confidence
  1. This vulnerability affects D-Link DIR-859 firmware version 1.05b03, which is explicitly noted as affecting products no longer supported by D-Link.
  2. No vendor patch or firmware upgrade is available for this vulnerability as the product has reached end-of-life.
  3. If you must continue using this device, restrict network access to the device's management interface by placing it behind a firewall and limiting access to trusted IP addresses only.
  4. Consider replacing the EOL D-Link DIR-859 with a currently supported router that receives security updates.
Caveat The product is end-of-life with no vendor support; replacement is the only secure option.

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

Fix this in Dir 859 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,820
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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-2023-36092 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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