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Dual Dhcp Dns ServerApplication · Dual Dhcp Dns Server Project

CVE-2020-26133

HIGH · 7.8 CVSS v3.1 Published 2020-10-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
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
An issue was discovered in Dual DHCP DNS Server 7.40. Due to insufficient access restrictions in the default installation directory, an attacker can elevate privileges by replacing the DualServer.exe binary.

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

In Dual DHCP DNS Server 7.40, the default installation directory has insufficient access restrictions that allow unprivileged local attackers to overwrite the DualServer.exe binary. When the service executes (typically with elevated privileges), it runs the attacker-modified executable, achieving privilege escalation.

MitigationRestrict write permissions on the DualServer installation directory to administrators only, removing modify/write access for standard users. Verify the integrity of DualServer.exe and restart the service.

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
Dual Dhcp Dns ServerApplication
Affected:= 7.40

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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. Locate DualServer.exe
    Check common installation paths for DualServer.exe, typically C:\Program Files\Dual DHCP DNS Server\ or C:\Program Files (x86)\Dual DHCP DNS Server\
    Affected if DualServer.exe exists in an unprotected directory
  2. Verify installed version
    Right-click DualServer.exe, select Properties, and check the File version on the Details tab. Confirm it is version 7.40
    Affected if Version is 7.40
  3. Inspect directory permissions
    Right-click the installation folder containing DualServer.exe, select Properties, go to the Security tab, and examine the permissions for Users or standard user accounts. Check if they have Write or Modify permissions
    Affected if Users or standard accounts have Write or Modify permission on the installation directory

If DualServer.exe version 7.40 is installed and standard users have Write or Modify permissions on its directory, the system is vulnerable to privilege escalation via binary replacement.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict write permissions on the DualServer installation directory to administrators only, removing modify/write access for standard users. Verify the integrity of DualServer.exe and restart the service.

Fix this in Dual Dhcp Dns Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,090
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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-2020-26133 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
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