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Dnr 202l FirmwareOperating system · Dlink

CVE-2026-4210

CRITICAL · 9.8 CVSS v3.1 Published 2026-03-16
Fix available
A fix is available. Upgrade to after 2026-02-05 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 DNS-120, DNR-202L, DNS-315L, DNS-320, DNS-320L, DNS-320LW, DNS-321, DNR-322L, DNS-323, DNS-325, DNS-326, DNS-327L, DNR-326, DNS-340L, DNS-343, DNS-345, DNS-726-4, DNS-1100-4, DNS-1200-05 and DNS-1550-04 up to 20260205. Affected by this vulnerability is the function cgi_tm_set_share of the file /cgi-bin/time_machine.cgi. The manipulation of the argument Name results in command injection. It is possible to launch the attack remotely. The exploit has been released to the public and may be used for attacks.

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

A command injection vulnerability exists in D-Link DNS-120, DNR-202L, DNS-315L, DNS-320, DNS-320L, DNS-320LW, DNS-321, DNR-322L, DNS-323, DNS-325, DNS-326, DNS-327L, DNR-326, DNS-340L, DNS-343, DNS-345, DNS-726-4, DNS-1100-4, DNS-1200-05, and DNS-1550-04 devices. The cgi_tm_set_share function in /cgi-bin/time_machine.cgi does not properly sanitize the Name argument, allowing remote attackers to execute arbitrary commands via crafted requests. The CVSS 9.8 score indicates critical severity, and public exploits are available.

MitigationIf a vendor patch is unavailable, isolate affected devices on a restricted network segment, disable the time_machine.cgi endpoint if possible, or replace end-of-life devices. Contact D-Link support to confirm patch availability.

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
Dnr 202l FirmwareOperating system
Affected:<= 2026-02-05
Dnr 326 FirmwareOperating system
Affected:<= 2026-02-05
Dns 1100 4 FirmwareOperating system
Affected:<= 2026-02-05
Dns 120 FirmwareOperating system
Affected:<= 2026-02-05
Dns 1200 05 FirmwareOperating system
Affected:<= 2026-02-05
Dns 1550 04 FirmwareOperating system
Affected:<= 2026-02-05
Dns 315l FirmwareOperating system
Affected:<= 2026-02-05
Dns 320 FirmwareOperating system
Affected:<= 2026-02-05

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 device model
    Access the device web interface or check the device label/menu for the exact model number. Common affected models include DNS-320, DNS-325, DNS-340L, DNR-202l, DNR-326, DNS-1100, DNS-120, DNS-1200, DNS-1550, DNS-315l.
    Affected if The device is one of the listed D-Link NAS models.
  2. Check firmware version
    Log into the device web admin panel and navigate to System > Firmware or Status page to view the installed firmware version and build date.
    Affected if Firmware version date is 2026-02-05 or earlier, or the version number falls within the affected range.
  3. Verify time_machine.cgi accessibility
    Attempt to access https://<device-ip>/cgi-bin/time_machine.cgi from the network. Check if the endpoint responds (even with an error).
    Affected if The endpoint is reachable and returns any HTTP response, indicating the CGI script is active.
  4. Assess network exposure
    Review firewall rules and network configuration to determine if the device web interface (port 80/443) is exposed to untrusted networks or the internet.
    Affected if The device web interface is accessible from untrusted networks without firewall restrictions.

The device is affected if it is a D-Link NAS model from the list, runs firmware dated 2026-02-05 or earlier, and has the time_machine.cgi endpoint 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.

dbcve · scoped
Upgrade available Upgrade to a release after 2026-02-05
Interim mitigation

If a vendor patch is unavailable, isolate affected devices on a restricted network segment, disable the time_machine.cgi endpoint if possible, or replace end-of-life devices. Contact D-Link support to confirm patch availability.

Recommended fix Moderate confidence

Latest firmware version released by D-Link for the specific model after 2026-02-05

  1. 1. Identify the exact model number of your D-Link device from the affected list (DNR-202L, DNS-120, DNS-315L, DNS-320, DNS-320L, DNS-320LW, DNS-321, DNR-322L, DNS-323, DNS-325, DNS-326, DNS-327L, DNR-326, DNS-340L, DNS-343, DNS-345, DNS-726-4, DNS-1100-4, DNS-1200-05, DNS-1550-04)
  2. 2. Visit the official D-Link support website at www.dlink.com and navigate to the firmware download section for your specific model
  3. 3. Check for firmware versions released after February 2026 (version date newer than 20260205)
  4. 4. Download the latest available firmware for your device model
  5. 5. Access the device's web administration interface
  6. 6. Navigate to the firmware upgrade section (typically under Settings or Administration)
  7. 7. Upload and apply the new firmware version
  8. 8. After upgrade, verify the cgi-bin/time_machine.cgi endpoint is no longer vulnerable by confirming the Name parameter is properly sanitized
Caveat Firmware upgrades on older D-Link devices may result in reset to factory defaults; backup configuration before upgrading if possible

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

Fix this in Dnr 202l Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,380
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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-2026-4210 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