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Dir 645 FirmwareOperating system · Dlink

CVE-2023-36089

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-645 firmware version 1.03 allows remote attackers to gain escalated privileges via function phpcgi_main in cgibin. 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

D-Link DIR-645 firmware version 1.03 contains an authentication bypass vulnerability in the phpcgi_main function within cgibin. This allows remote, unauthenticated attackers to bypass authentication controls and gain escalated privileges on affected devices.

MitigationSince this product is end-of-life and no longer supported by D-Link, replace affected devices with currently supported models. If immediate replacement is not feasible, isolate affected devices behind a firewall and disable WAN management access to reduce 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 645 FirmwareOperating system
Affected:= 1.03

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
    Access the device admin interface or check the device label/packaging for the firmware version. If accessing the web interface, look for a 'Status' or 'Firmware' section that displays the current version.
    Affected if The installed firmware version is exactly 1.03
  2. Confirm the device model
    Verify that the affected device is specifically the D-Link DIR-645 router. Check the device label or web interface for the exact model number.
    Affected if The device model is D-Link DIR-645 with firmware version 1.03
  3. Check if the web management interface is network-accessible
    Attempt to access the device's web interface from a remote network location, or review firewall/network rules to determine if ports 80 or 443 (HTTP/HTTPS) are exposed to untrusted networks.
    Affected if The cgibin web interface is reachable from untrusted networks (such as the internet) and the firmware is version 1.03
  4. Verify remote management settings
    Log into the device admin interface and navigate to the management/administration settings to check if 'Remote Management' or 'WAN Management' is enabled.
    Affected if Remote management access is enabled on a device running firmware version 1.03

A device is affected if it is a D-Link DIR-645 running firmware version 1.03 and its web management interface (cgibin) is accessible from untrusted networks.

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 product is end-of-life and no longer supported by D-Link, replace affected devices with currently supported models. If immediate replacement is not feasible, isolate affected devices behind a firewall and disable WAN management access to reduce exposure.

Recommended fix High confidence
  1. Replace the D-Link DIR-645 device with a currently supported model from D-Link or another vendor, as this device is end-of-life and no longer receives security updates.
  2. If immediate replacement is not possible, isolate the device on a restricted network segment with firewall rules limiting access to trusted IP addresses only.
  3. Disable remote management interfaces if not required, restricting access to local network only.
Caveat The DIR-645 is end-of-life with no further firmware updates available; replacement with a currently supported device is required

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

Fix this in Dir 645 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2023-36089 in production — separate from our analysis above.

No notes yet

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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