Vigor3910 FirmwareOperating system · Draytek

CVE-2024-46583

HIGH · 7.5 CVSS v3.1 Published 2024-09-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the extRadSrv2 parameter at cgiapp.cgi. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted input.

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

A buffer overflow vulnerability exists in the Draytek Vigor 3910 router's web interface (cgiapp.cgi) in the extRadSrv2 parameter. Attackers can send a crafted input exceeding expected buffer bounds, causing the service to crash and resulting in denial of service. The vulnerability is remotely exploitable without authentication given it's in the unauthenticated CGI handling.

MitigationApply the vendor-supplied firmware patch when available. Until then, restrict access to the web management interface via firewall rules or ACLs to trusted IPs only, and monitor for signs of exploitation attempts.

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
Vigor3910 FirmwareOperating system
Affected:= 4.3.2.6

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 router's web interface or check the administrative console to confirm the device is a Draytek Vigor 3910. This can often be determined by accessing the login page or checking system status information.
    Affected if The device is not a Draytek Vigor 3910, the vulnerability does not apply.
  2. Check the installed firmware version
    Navigate to the router's web interface, typically at the management IP, and locate the firmware version in the system status or maintenance section. Alternatively, check via CLI if accessible: 'sys cat /proc/version' or similar command depending on available access.
    Affected if The firmware version is exactly 4.3.2.6, matching the affected version.
  3. Determine if the web management interface is exposed
    Verify whether the router's web interface (cgiapp.cgi) is accessible from untrusted networks. Check firewall rules, port forwarding settings, or WAN accessibility. Attempt to access http(s)://<router-ip>/cgiapp.cgi from an external location or review network exposure configuration.
    Affected if The web interface is accessible from untrusted networks (internet-facing or untrusted LAN segments), making exploitation possible.
  4. Check for service crashes or anomalies
    Review router logs for signs of crashes, restarts, or abnormal behavior. Look for entries around cgiapp.cgi processing, extRadSrv2 parameter errors, or unexpected service interruptions in the system logs.
    Affected if The router exhibits unexplained crashes, restarts, or log entries mentioning cgiapp.cgi failures, which may indicate exploitation attempts.
  5. Monitor for suspicious CGI requests
    If log access is available, inspect HTTP access logs or traffic captures for requests to cgiapp.cgi containing unusually long or malformed extRadSrv2 parameter values.
    Affected if Logs show requests to cgiapp.cgi with abnormally long extRadSrv2 values, indicating potential exploitation activity.

A user is affected if they are running Draytek Vigor 3910 firmware version 4.3.2.6 with the web management interface exposed to untrusted networks, or if they observe crash logs or suspicious CGI requests related to extRadSrv2.

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

Apply the vendor-supplied firmware patch when available. Until then, restrict access to the web management interface via firewall rules or ACLs to trusted IPs only, and monitor for signs of exploitation attempts.

Fix this in Vigor3910 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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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-2024-46583 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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