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Dir 816 FirmwareOperating system · Dlink

CVE-2025-5620

CRITICAL · 9.8 CVSS v3.1 Published 2025-06-05
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
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 vulnerability, which was classified as critical, was found in D-Link DIR-816 1.10CNB05. Affected is the function setipsec_config of the file /goform/setipsec_config. The manipulation of the argument localIP/remoteIP leads to os command injection. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. 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

OS command injection vulnerability in D-Link DIR-816 router (firmware 1.10CNB05) allows unauthenticated remote attackers to execute arbitrary commands via the localIP/remoteIP parameters in the /goform/setipsec_config endpoint. The IPSec configuration function fails to sanitize user input before passing it to system shell commands.

MitigationThis affects end-of-life hardware with no vendor support; replace affected devices with currently-supported models. If immediate replacement is not feasible, disable the IPSec VPN functionality and restrict network access to the device management interface.

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 816 FirmwareOperating system
Affected:= 1.10cnb05

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
    Access the router web interface or check the device label to confirm it is a D-Link DIR-816 model.
    Affected if The device is not a D-Link DIR-816 router.
  2. Check the firmware version
    Log into the router web interface and navigate to the Status or System section to view the firmware version. Alternatively, check the firmware file name if you have access to the firmware binary.
    Affected if The firmware version is NOT 1.10CNB05 exactly.
  3. Verify IPSec VPN functionality is enabled
    Log into the router web interface and check the VPN or IPSec settings. Look for any configured IPSec VPN tunnels or policies.
    Affected if IPSec VPN is not configured or enabled on the device.
  4. Test for vulnerable endpoint accessibility
    Attempt to access or send a request to the /goform/setipsec_config endpoint from the local network. This requires authenticated access to the router admin interface.
    Affected if The /goform/setipsec_config endpoint responds or accepts configuration input.

A user is affected if they have a D-Link DIR-816 router running firmware version 1.10CNB05 with IPSec VPN functionality enabled and the vulnerable endpoint accessible.

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

This affects end-of-life hardware with no vendor support; replace affected devices with currently-supported models. If immediate replacement is not feasible, disable the IPSec VPN functionality and restrict network access to the device management interface.

Recommended fix High confidence

Replace with a currently-supported D-Link router or alternative brand that provides active security firmware updates

  1. 1. Immediately disconnect the affected D-Link DIR-816 device from the network to prevent remote exploitation.
  2. 2. Since this firmware version (1.10cnb05) is End-of-Life and no longer supported by D-Link, there will be no official security patch.
  3. 3. Replace the affected device with a currently-supported router model that receives regular security updates.
  4. 4. If replacement is not immediately possible, restrict network access to the device's management interface by placing it behind a firewall or using ACLs to limit access to trusted IP addresses only.
  5. 5. Disable the IPSec functionality (the vulnerable feature) if not required, through the device's web interface.
  6. 6. Monitor D-Link's security advisories periodically for any unexpected firmware releases, though none are expected for this EOL product.
Caveat The DIR-816 1.10cnb05 is End-of-Life with no security support; no firmware upgrade path exists; device replacement is required

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

Fix this in Dir 816 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,060
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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-2025-5620 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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