Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 4 Mar 2025.
Vmg1312 B10a FirmwareOperating system · Zyxel

CVE-2024-40890

HIGH · 8.8 CVSS v3.1 Published 2025-02-04
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
In the wild Remotely reachable 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
**UNSUPPORTED WHEN ASSIGNED** A post-authentication command injection vulnerability in the CGI program of the legacy DSL CPE Zyxel VMG4325-B10A firmware version 1.00(AAFR.4)C0_20170615 could allow an authenticated attacker to execute operating system (OS) commands on an affected device by sending a crafted HTTP POST request.

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

Post-authentication command injection in Zyxel VMG4325-B10A CGI program allows authenticated attackers to execute arbitrary OS commands via crafted HTTP POST requests. The vulnerability stems from insufficient input sanitization in the web interface's CGI component.

MitigationDevice is END-OF-LIFE and receives no vendor patches. Mitigate by replacing with a supported device, or implement network segmentation and restrict administrative access to trusted IP addresses only.

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
Vmg1312 B10a FirmwareOperating system
Affected:all versions
Vmg1312 B10b FirmwareOperating system
Affected:all versions
Vmg1312 B10e FirmwareOperating system
Affected:all versions
Vmg3312 B10a FirmwareOperating system
Affected:all versions
Vmg3313 B10a FirmwareOperating system
Affected:all versions
Vmg3926 B10b FirmwareOperating system
Affected:all versions
Vmg4325 B10a FirmwareOperating system
Affected:all versions
Vmg4380 B10a FirmwareOperating system
Affected:all versions

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/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. Identify the device model
    Log into the router web interface and check the Status or Device Info page for the exact model number (e.g., VMG4325-B10A, VMG1312-B10A). Alternatively, check the physical device label on the device itself.
    Affected if The model is any of: Vmg1312 B10a, Vmg1312 B10b, Vmg1312 B10e, Vmg3312 B10a, Vmg3313 B10a, Vmg3926 B10b, Vmg4325 B10a, or Vmg4380 B10a.
  2. Verify the CGI web interface is accessible
    Attempt to access the router's web login page from the network segment where management is expected (typically http://192.168.1.1 or the router's LAN IP). Confirm the page loads and presents a login form.
    Affected if The CGI web interface responds and accepts authentication requests, indicating the vulnerable component is active.
  3. Check if remote management is enabled
    In the web UI, navigate to Network Settings > Remote Management or Administration > Remote Access. Look for settings that enable HTTP/HTTPS management from WAN/outside interfaces.
    Affected if Remote management (WAN access) is enabled on the router, allowing the vulnerability to be exploited from external networks.
  4. Confirm authentication is active
    Verify that the web interface requires login credentials and that default or configured admin accounts are enabled. Check if the authentication mechanism is functional.
    Affected if The device accepts authentication, which is a prerequisite for exploiting this post-authentication command injection flaw.

The device is affected if it is one of the listed Zyxel VMG models and the CGI web management interface is accessible, especially if remote WAN 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.

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

Device is END-OF-LIFE and receives no vendor patches. Mitigate by replacing with a supported device, or implement network segmentation and restrict administrative access to trusted IP addresses only.

Fix this in Vmg1312 B10a Firmware Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2024-40890 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
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