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Cbr40 FirmwareOperating system · Netgear

CVE-2021-38527

CRITICAL · 9.8 CVSS v3.1 Published 2021-08-11
Fix available
A fix is available. Upgrade to 1.0.0.132 / 1.0.1.98 or later.
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
Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR40 before 2.5.0.14, EX6100v2 before 1.0.1.98, EX6150v2 before 1.0.1.98, EX6250 before 1.0.0.132, EX6400 before 1.0.2.158, EX6400v2 before 1.0.0.132, EX6410 before 1.0.0.132, EX6420 before 1.0.0.132, EX7300 before 1.0.2.158, EX7300v2 before 1.0.0.132, EX7320 before 1.0.0.132, EX7700 before 1.0.0.216, EX8000 before 1.0.1.232, R7800 before 1.0.2.78, RBK12 before 2.6.1.44, RBR10 before 2.6.1.44, RBS10 before 2.6.1.44, RBK20 before 2.6.1.38, RBR20 before 2.6.1.36, RBS20 before 2.6.1.38, RBK40 before 2.6.1.38, RBR40 before 2.6.1.36, RBS40 before 2.6.1.38, RBK50 before 2.6.1.40, RBR50 before 2.6.1.40, RBS50 before 2.6.1.40, RBK752 before 3.2.16.6, RBR750 before 3.2.16.6, RBS750 before 3.2.16.6, RBK852 before 3.2.16.6, RBR850 before 3.2.16.6, RBS850 before 3.2.16.6, RBS40V before 2.6.2.4, RBS50Y before 2.6.1.40, RBW30 before 2.6.2.2, and XR500 before 2.3.2.114.

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

This is an OS command injection vulnerability in multiple NETGEAR router, extender, and mesh system devices that allows unauthenticated attackers to execute arbitrary system commands by injecting malicious input into vulnerable parameters. The flaw stems from improper input validation in the device firmware's web management interface.

MitigationApply the appropriate firmware update for each affected device model as specified in the vendor advisory; for devices that have reached end-of-life, consider replacement with supported hardware.

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
Cbr40 FirmwareOperating system
Affected:< 2.5.0.14
Ex6100 FirmwareOperating system
Affected:< 1.0.1.98
Ex6150 FirmwareOperating system
Affected:< 1.0.1.98
Ex6250 FirmwareOperating system
Affected:< 1.0.0.132
Ex6400 FirmwareOperating system
Affected:< 1.0.2.158< 1.0.0.132
Ex6410 FirmwareOperating system
Affected:< 1.0.0.132
Ex6420 FirmwareOperating system
Affected:< 1.0.0.132
Ex7300 FirmwareOperating system
Affected:< 1.0.2.158

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 NETGEAR device model
    Locate the device label on the physical device or access the router's web management interface to confirm the exact model number (Cbr40, Ex6100, Ex6150, Ex6250, Ex6400, Ex6410, Ex6420, or Ex7300)
    Affected if The device model matches one of the affected models listed in the CVE advisory
  2. Check the installed firmware version
    Access the router's web-based admin interface (typically at 192.168.1.1 or 192.168.1.0), navigate to the Administration or Settings section, and locate the firmware version information
    Affected if The displayed firmware version falls below the version thresholds: Cbr40 < 2.5.0.14, Ex6100 < 1.0.1.98, Ex6150 < 1.0.1.98, Ex6250 < 1.0.0.132, Ex6400 < 1.0.2.158 (or < 1.0.0.132 for certain variants), Ex6410 < 1.0.0.132, Ex6420 < 1.0.0.132, Ex7300 < 1.0.2.158
  3. Verify the web management interface is reachable
    Attempt to access the device's web admin URL (http or https) from a connected client on the local network
    Affected if The web management interface is accessible, which is the default configuration on these devices and is required for the command injection to be exploitable

If your device is one of the affected models (Cbr40, Ex6100, Ex6150, Ex6250, Ex6400, Ex6410, Ex6420, or Ex7300) AND its firmware version is below the specified threshold, your device is vulnerable to unauthenticated command injection via the web management interface.

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
Upgrade available Upgrade to 1.0.0.132 / 1.0.1.98 / 1.0.2.158 or later
Fixed in 1.0.0.1321.0.1.981.0.2.158
Interim mitigation

Apply the appropriate firmware update for each affected device model as specified in the vendor advisory; for devices that have reached end-of-life, consider replacement with supported hardware.

Recommended fix High confidence

Device-specific firmware: CBR40: 2.5.0.14+ | EX6100v2/EX6150v2: 1.0.1.98+ | EX6250/EX6400v2/EX6410/EX6420/EX7300v2/EX7320: 1.0.0.132+ | EX6400/EX7300: 1.0.2.158+ | EX7700: 1.0.0.216+ | EX8000: 1.0.1.232+ | R7800: 1.0.2.78+ | Orbi (RBK12/RBR10/RBS10): 2.6.1.44+ | Orbi (RBK20/RBR20/RBS20/RBK40/RBR40/R

  1. 1. Identify the exact NETGEAR device model (e.g., CBR40, EX6400, R7800) from the affected product list
  2. 2. Determine the current firmware version by accessing the device web interface or checking the device label
  3. 3. Navigate to the NETGEAR support page: https://www.netgear.com/support/
  4. 4. Enter the specific device model in the search box to locate the firmware download page
  5. 5. Download the firmware version equal to or newer than the fixed version for your device (e.g., CBR40: 2.5.0.14+, EX6400: 1.0.2.158+, EX7300: 1.0.2.158+)
  6. 6. Access the device admin interface (typically at http://routerlogin.net or http://192.168.1.1)
  7. 7. Navigate to the Administration > Firmware Update section
  8. 8. Select the downloaded firmware file and initiate the update
Caveat Firmware updates may reset device configuration; backup settings before updating if possible

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

Fix this in Cbr40 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,880
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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-2021-38527 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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  • No spam, self-promotion, credentials, or personal data