dbcve.org
Re6400 FirmwareOperating system · Linksys

CVE-2019-11535

CRITICAL · 9.8 CVSS v3.0 Published 2019-07-17
Fix available
A fix is available. Upgrade to after 1.2.04.022 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
Unsanitized user input in the web interface for Linksys WiFi extender products (RE6400 and RE6300 through 1.2.04.022) allows for remote command execution. An attacker can access system OS configurations and commands that are not intended for use beyond the web UI.

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

Command injection vulnerability in the web interface of Linksys WiFi extenders RE6400 and RE6300 (firmware through 1.2.04.022) allows unauthenticated remote attackers to execute arbitrary OS commands via unsanitized user input fields that are passed to system shell.

MitigationApply vendor firmware update if available; if unsupported, disable remote web interface access (change to local-only administration) and segment device on isolated network VLAN.

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
Re6400 FirmwareOperating system
Affected:<= 1.2.04.022
Re6300 FirmwareOperating system
Affected:<= 1.2.04.022

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:3.0/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 device model
    Access the device's web interface or check the device label to confirm it is a Linksys RE6400 or RE6300 WiFi extender
    Affected if The device is a Linksys RE6400 or RE6300 model
  2. Check the installed firmware version
    Log into the web interface and navigate to Status or Administration > Firmware Upgrade to view the current firmware version, or use the command 'cat /proc/version' or 'nvram get firmware_version' if SSH/telnet access is available
    Affected if The firmware version is 1.2.04.022 or earlier (any version <= 1.2.04.022)
  3. Verify the web interface is accessible
    Attempt to access the device's web interface by entering the extender's IP address in a web browser
    Affected if The web interface responds and accepts input on any port (typically HTTP port 80)
  4. Check if remote administration is enabled
    In the web interface, go to Administration > Remote Management to see if remote access to the web interface is permitted from external IP addresses
    Affected if Remote management is enabled and the web interface is reachable from outside the local network

A user is affected if they have a Linksys RE6400 or RE6300 device running firmware version 1.2.04.022 or earlier, with the web interface accessible (especially if remote management is enabled).

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 a release after 1.2.04.022
Interim mitigation

Apply vendor firmware update if available; if unsupported, disable remote web interface access (change to local-only administration) and segment device on isolated network VLAN.

Recommended fix Moderate confidence

Latest available firmware from Linksys (version > 1.2.04.022)

  1. Identify your exact model number (RE6400 or RE6300) from the device label
  2. Navigate to the official Linksys support website (linksys.com)
  3. Locate the firmware download section for your specific model
  4. Download the latest available firmware version (must be higher than 1.2.04.022)
  5. Access the web interface of your extender by connecting to its network
  6. Navigate to Administration > Firmware Upgrade
  7. Upload and apply the new firmware file
  8. After reboot, verify the firmware version in the web interface
Caveat Firmware upgrades may reset device configuration to defaults; back up settings if possible before upgrading

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

Fix this in Re6400 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,690
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,304.

Scan for this in your stack

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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-2019-11535 in production — separate from our analysis above.

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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