Improper Access ControlWeakness · CWE-284

CVE-2025-29524

MEDIUM · 6.5 CVSS v3.1 Published 2025-08-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
74/100
Remediation priority · Elevated
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
Incorrect access control in the component /cgi-bin/system_diagnostic_main.asp of DASAN GPON ONU H660WM H660WMR210825 allows attackers to access sensitive information.

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 vulnerability exists in the CGI script /cgi-bin/system_diagnostic_main.asp on DASAN GPON ONU H660WM and H660WMR210825 devices. Due to incorrect access control implementation, unauthenticated attackers can access this diagnostic page and retrieve sensitive system information without proper authorization.

MitigationApply vendor firmware patch when available; until then, restrict network access to the device management interface using firewall rules or VLAN segmentation to prevent unauthorized access to the /cgi-bin/ endpoints.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

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 web interface or check the device label/sticker for the model number. Look for 'H660WM' or 'H660WMR210825' markings indicating DASAN GPON ONU hardware.
    Affected if The device is a DASAN GPON ONU H660WM or H660WMR210825 model.
  2. Verify the CGI script exists
    Send an HTTP GET request to http://<device_ip>/cgi-bin/system_diagnostic_main.asp without providing any authentication credentials. Check if the server responds with HTTP 200 and returns diagnostic content.
    Affected if The endpoint returns diagnostic or system information without requiring login credentials.
  3. Confirm the page contains sensitive data
    Examine the response from the /cgi-bin/system_diagnostic_main.asp endpoint. Look for system configuration, firmware version, network settings, or other sensitive information that should require authentication.
    Affected if The page displays system details such as firmware version, network configuration, device status, or other sensitive parameters without being logged in.
  4. Check if default credentials are not required
    Attempt to access the diagnostic page after deliberately failing or omitting login credentials. Verify that no authentication challenge (HTTP 401, redirect to login page, or session check) blocks the request.
    Affected if The diagnostic page is accessible without any valid session token or login credentials.

A user is affected if they operate a DASAN H660WM or H660WMR210825 device where the /cgi-bin/system_diagnostic_main.asp endpoint returns sensitive system information to unauthenticated requests.

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 vendor firmware patch when available; until then, restrict network access to the device management interface using firewall rules or VLAN segmentation to prevent unauthorized access to the /cgi-bin/ endpoints.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,420
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,872.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-29524 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2025-29524 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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