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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 21 Apr 2022.
Gpon Router FirmwareOperating system · Dasannetworks

CVE-2018-10561

CRITICAL · 9.8 CVSS v3.1 Published 2018-05-04
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 High EPSS Public exploit 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
An issue was discovered on Dasan GPON home routers. It is possible to bypass authentication simply by appending "?images" to any URL of the device that requires authentication, as demonstrated by the /menu.html?images/ or /GponForm/diag_FORM?images/ URI. One can then manage the device.

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

Dasan GPON home routers contain an authentication bypass vulnerability where adding the query parameter '?images' to any protected URL path (such as /menu.html or /GponForm/diag_FORM) allows unauthenticated access to administrative interfaces and device management functions.

MitigationApply vendor firmware updates if available; otherwise restrict network access to device management interfaces via firewall rules or VLAN segmentation, or replace unsupported devices.

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
Gpon Router 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
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. Identify Dasan GPON routers on your network
    Inventory all network devices and check if any are Dasan GPON home router models. Use network scanning, device discovery tools, or check physical device labels for model numbers.
    Affected if Any Dasan GPON router model is found on the network
  2. Verify the device runs GPON firmware
    Access the router admin interface or check device documentation to confirm the firmware is designed for GPON functionality.
    Affected if The device runs GPON firmware from Dasan Networks
  3. Test authentication bypass with the known pattern
    From an unauthenticated browser session, attempt to access a normally-protected page by appending ?images/ to the URL path, such as http://router-ip/menu.html?images/ or http://router-ip/GponForm/diag_FORM?images/
    Affected if The page loads without requiring login credentials
  4. Check if management interface is network-accessible
    Determine if the router web management interface (port 80/443) is reachable from untrusted network segments or the internet by scanning external-facing IP ranges or reviewing firewall rules.
    Affected if The router admin interface is exposed to untrusted networks without access controls

Your environment is affected if you have Dasan GPON routers and the management interface is accessible, allowing the ?images/ bypass to grant unauthenticated access to device functions.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor firmware updates if available; otherwise restrict network access to device management interfaces via firewall rules or VLAN segmentation, or replace unsupported devices.

Recommended fix High confidence
  1. Confirm the device model and firmware version by accessing the router administration interface
  2. Contact your Internet Service Provider (ISP) to request a firmware update or a replacement router, as Dasan GPON routers are often provided/supported by ISPs
  3. If ISP support is unavailable, replace the affected GPON router with a newer model from a vendor that provides regular security updates
  4. As an interim mitigation, disable remote management interfaces (WAN access) on the router if not required for network operations
  5. If remote management is required, implement network segmentation by placing the router behind a firewall and restricting management access to VPN-connected management networks only
  6. Monitor for indicators of compromise such as unauthorized configuration changes or unfamiliar admin accounts
Caveat Consumer-grade Dasan GPON routers provided by ISPs often have no available firmware updates; replacement may be necessary

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

Fix this in Gpon Router Firmware Exploited in the wild — priority engagement
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
27.0 hours of engineering $4,800
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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-2018-10561 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