Ac21000 G6 FirmwareOperating system · Connectize

CVE-2023-24051

CRITICAL · 9.8 CVSS v3.1 Published 2023-12-04
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
A client side rate limit issue discovered in Connectize AC21000 G6 641.139.1.1256 allows attackers to gain escalated privileges via brute force style attacks.

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

The Connectize AC21000 G6 router firmware 641.139.1.1256 implements rate limiting only on the client side (likely in JavaScript or browser-based validation) rather than enforcing it server-side. This allows attackers to bypass the rate limits and perform unlimited login attempts, enabling brute force attacks to successfully escalate privileges.

MitigationImplement server-side rate limiting with account lockout policies, enforce throttling at the API/gateway level, and replace client-side validation with server-side authentication controls. Check vendor for firmware updates.

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
Ac21000 G6 FirmwareOperating system
Affected:= 641.139.1.1256

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. Check installed firmware version
    Access router admin panel (typically at 192.168.0.1 or 192.168.1.1), navigate to System Status, About, or Firmware Update page. Alternatively, check via CLI if SSH/Telnet is enabled: `router_firmware_version` or `cat /proc/version` if accessible.
    Affected if Firmware version is exactly 641.139.1.1256
  2. Identify login rate limiting mechanism
    Navigate to router security settings, login configuration, or access control panel. Look for rate limiting, login attempt limits, or brute force protection settings. Document whether these controls appear to be enforced server-side or client-side (JavaScript/browser-based).
    Affected if Rate limiting is enforced client-side only (JavaScript validation) with no server-side enforcement visible in configuration
  3. Verify server-side rate limiting configuration
    Check for server-side throttling settings in router security or firewall configuration. Look for API rate limiting, connection limiting, or login attempt throttling at the gateway level. If available, confirm it is actively applied to authentication endpoints.
    Affected if No server-side rate limiting is configured or it is absent from security settings
  4. Test for brute force protection
    Attempt multiple rapid login attempts (e.g., 20+ failed attempts) using a testing account or observing if the system blocks or throttles requests server-side. Check logs if accessible for evidence of rate limiting enforcement.
    Affected if Unlimited login attempts are possible without server-side blocking or throttling occurring

Environment is affected if the firmware version is exactly 641.139.1.1256 AND only client-side rate limiting exists without server-side enforcement or account lockout policies.

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

Implement server-side rate limiting with account lockout policies, enforce throttling at the API/gateway level, and replace client-side validation with server-side authentication controls. Check vendor for firmware updates.

Fix this in Ac21000 G6 Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
34.0 hours of engineering $6,000
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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-2023-24051 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
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  • Version or environment caveats, and links to real fixes
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