Dir 825 FirmwareOperating system · Dlink

CVE-2025-10666

CRITICAL · 9.8 CVSS v3.1 Published 2025-09-18
Fix available
A fix is available. Upgrade to after 2.10 or later.
See remediation →
100/100
Remediation priority · Urgent
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
A security flaw has been discovered in D-Link DIR-825 up to 2.10. Affected by this vulnerability is the function sub_4106d4 of the file apply.cgi. The manipulation of the argument countdown_time results in buffer overflow. The attack can be executed remotely. The exploit has been released to the public and may be exploited. This vulnerability only affects products that are no longer supported by the maintainer.

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

Buffer overflow vulnerability in D-Link DIR-825 (up to v2.10) apply.cgi function sub_4106d4 allows remote code execution via manipulated countdown_time argument. The flaw is remotely exploitable without authentication and a public exploit exists.

MitigationSince the device is end-of-life with no vendor patch available, remediation requires either device replacement with supported hardware or compensating controls such as network segmentation and aggressive access restrictions to limit exposure.

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
Dir 825 FirmwareOperating system
Affected:<= 2.10

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 the device model
    Check the device label on the physical hardware or log into the router web interface and look for the model number in the status or system information page
    Affected if The device is not a D-Link DIR-825 model, then it is not affected by this specific CVE
  2. Check the firmware version
    In the router web interface, navigate to Status or System settings and locate the firmware version field. Alternatively, check the firmware file name if you have access to the firmware image
    Affected if The firmware version is 2.10 or lower, making it within the affected range (<= 2.10)
  3. Verify apply.cgi endpoint accessibility
    Attempt to access http://[router-ip]/apply.cgi by sending a request. A vulnerable device will respond to this endpoint
    Affected if The apply.cgi endpoint is reachable and responds, indicating the web interface is active and potentially exploitable
  4. Confirm the countdown_time parameter handling exists
    Send a crafted request to apply.cgi with a manipulated countdown_time parameter. A vulnerable device will process this parameter without authentication
    Affected if The device accepts and processes the countdown_time argument in apply.cgi without requiring authentication

The device is affected if it is a D-Link DIR-825 running firmware version 2.10 or lower and the apply.cgi web interface is accessible on the network.

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
Upgrade available Upgrade to a release after 2.10
Interim mitigation

Since the device is end-of-life with no vendor patch available, remediation requires either device replacement with supported hardware or compensating controls such as network segmentation and aggressive access restrictions to limit exposure.

Fix this in Dir 825 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
25.0 hours of engineering $4,400
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-10666 — 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-2025-10666 in production — separate from our analysis above.

No notes yet

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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