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Gs810emx FirmwareOperating system · Netgear

CVE-2018-21121

HIGH · 8.8 CVSS v3.1 Published 2020-04-22
Fix available
A fix is available. Upgrade to 1.0.0.5 / 1.0.0.6 or later.
See remediation →
93/100
Remediation priority · Urgent
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
Certain NETGEAR devices are affected by authentication bypass. This affects GS810EMX before 1.0.0.5, XS512EM before 1.0.0.6, and XS724EM before 1.0.0.6.

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 NETGEAR GS810EMX, XS512EM, and XS724EM network switch web management interfaces. Attackers can circumvent login authentication to gain unauthorized administrative access to device configuration. Specific vulnerability mechanics are not disclosed in available sources.

MitigationApply firmware updates: GS810EMX to version 1.0.0.5 or later, XS512EM to version 1.0.0.6 or later, XS724EM to version 1.0.0.6 or later. If updates unavailable, restrict network access to management interfaces via ACLs or VLAN isolation.

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
Gs810emx FirmwareOperating system
Affected:< 1.0.0.5
Xs512em FirmwareOperating system
Affected:< 1.0.0.6
Xs724em FirmwareOperating system
Affected:< 1.0.0.6

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

CVSS:3.1/AV:A/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 exact switch model
    Access the device web interface or CLI and confirm the model number is one of: GS810EMX, XS512EM, or XS724EM. This can typically be found in the System Information or Dashboard page of the web UI, or via 'show system-info' or similar command in CLI.
    Affected if Model is GS810EMX, XS512EM, or XS724EM - only these models are affected by this CVE.
  2. Locate firmware version in web management interface
    Log into the switch web UI and navigate to System or Administration section to find the firmware version displayed. Common paths include System > System Information or Maintenance > Device Information. Note the exact version string shown.
    Affected if Version information cannot be located - without confirming the firmware version, the vulnerability status cannot be determined.
  3. Compare GS810EMX firmware to vulnerable threshold
    If the device is a GS810EMX, compare the installed firmware version to 1.0.0.5. Versions below 1.0.0.5 are vulnerable. Ensure you compare the full version string including any build numbers.
    Affected if GS810EMX firmware version is below 1.0.0.5 - device is affected by this authentication bypass.
  4. Compare XS512EM firmware to vulnerable threshold
    If the device is an XS512EM, compare the installed firmware version to 1.0.0.6. Versions below 1.0.0.6 are vulnerable. Ensure you compare the full version string including any build numbers.
    Affected if XS512EM firmware version is below 1.0.0.6 - device is affected by this authentication bypass.
  5. Compare XS724EM firmware to vulnerable threshold
    If the device is an XS724EM, compare the installed firmware version to 1.0.0.6. Versions below 1.0.0.6 are vulnerable. Ensure you compare the full version string including any build numbers.
    Affected if XS724EM firmware version is below 1.0.0.6 - device is affected by this authentication bypass.

Device is affected if it is a GS810EMX running firmware below 1.0.0.5, an XS512EM below 1.0.0.6, or an XS724EM below 1.0.0.6, and its web management interface is accessible to 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.

From vendor data
Upgrade available Upgrade to 1.0.0.5 / 1.0.0.6 or later
Fixed in 1.0.0.51.0.0.6
Interim mitigation

Apply firmware updates: GS810EMX to version 1.0.0.5 or later, XS512EM to version 1.0.0.6 or later, XS724EM to version 1.0.0.6 or later. If updates unavailable, restrict network access to management interfaces via ACLs or VLAN isolation.

Fix this in Gs810emx Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2018-21121 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