Overview

On December 16, 2025, VulnCheck, a cybersecurity research firm, reported active exploitation involving a compromised CGI library observed in certain D-Link devices. D-Link began an internal investigation on the same day and is reviewing historical and current use of this CGI library across all relevant products.

VulnCheck (https://www.vulncheck.com/) identified this issue after observing exploitation activity in live network environments. At present, no reliable method exists to identify affected models by model number alone. Confirmation requires direct inspection of device firmware. For this reason, D-Link is reviewing firmware builds across both legacy and supported platforms as part of the investigation.

This issue relates to a broader class of attacks previously documented under the name GhostDNS. In January 2019, security researchers reported GhostDNS as a large-scale DNS hijacking system used for data theft. Netlab, an information security research organization, reported more than 100,000 affected routers worldwide, with a large concentration in Brazil. The affected devices included consumer and carrier-grade routers from multiple vendors, including D-Link.

Netlab also documented malware referred to as DNSChanger, which targets router configuration interfaces. This attack attempts to gain access by guessing default credentials such as admin/admin or root/root, or by bypassing authentication through exposed CGI endpoints such as dnscfg.cgi.

D-Link published security advisories and firmware updates addressing these issues in 2019:

      July 20, 2019 – Multiple products

             https://supportannouncement.us.dlink.com/security/publication.aspx?name=SAP10118

      December 27, 2019 – DSL-526B, DSL-2640B, DSL-2740R, DSL-2780B

           https://supportannouncement.us.dlink.com/security/publication.aspx?name=SAP10068

The recently referenced CVE-2026-0625 relates to the same general attack family as GhostDNS and DNSChanger. Many of the products cited in external reports reached end-of-life years ago and no longer receive firmware development or security updates.

GhostDNS represents an advanced evolution of DNSChanger. Researchers identified multiple variants, including shell-based DNSChanger and PyPhp DNSChanger. The PyPhp variant served as the primary module and operated across more than 100 command-and-control servers, largely hosted on cloud infrastructure. These variants included over 100 attack scripts designed to target routers on both public internet and internal networks.

Products associated with these vulnerabilities no longer receive updates or security maintenance. D-Link Systems, Inc. recommends retiring affected legacy devices and replacing them with supported products that receive regular firmware updates.

Some older D-Link devices previously affected by DNSChanger, and referenced again in relation to CVE-2026-0625 and GhostDNS-related activity, appear in third-party reports. Owners of such devices should review network security, verify firmware status, and take appropriate action based on individual risk and usage. For products sold in the US, you can get the last known assets prior to EOL/EOS at: https://legacy.us.dlink.com/ if an owner choose continued use at their own risks.  For owners of Non-US offered D-Link devices please contact your local regional office here, Then click the region choice icon in upper right corner. 

CVE-2026-0625 : Link : An unauthenticated remote attacker can inject and execute arbitrary shell commands, resulting in remote code execution. The affected endpoint is also associated with unauthenticated DNS modification (“DNSChanger”) behavior documented by D-Link, which reported active exploitation campaigns targeting firmware variants of the DSL-2740R, DSL-2640B, DSL-2780B, and DSL-526B models from 2016 through 2019. Exploitation evidence was observed by the Shadowserver Foundation on 2025-11-27 (UTC).

       DSL-526B (Non-US:: End of Service Life): 

       DSL-2640B (Non-US:: End of Service Life)

       DSL-2740R (Non-US:: End of Service Life)

       DSL-2780B(Non-US:: End of Service Life)

DNSChanger Shell:

     • D-LINK DSL-2640T (Non-US:: End of Service Life)
     • D-LINK DSL-2740R (Non-US:: End of Service Life)
     • D-LINK DSL-500 (Non-US:: End of Service Life)
     • D-LINK DSL-500G / DSL-502G  (Non-US & US:: End of Service Life) 

DNSChanger Js

      • D-Link DIR-905L :: (Non-US :: End of Service Life)

PyPhp DNSChanger:

•  D-Link DIR-600 (US :: End of Service Life :: LINK)
• D-Link DIR-600 (Non-US :: Rev. B :: End of Service Life)
• D-Link DIR-608  (Non-US :: End of Service Life)
• D-Link DIR-610  (Non-US ::: End of Service Life)
• D-Link DIR-611  (Non-US :: : End of Service Life)
• D-Link DIR-615  (Non-US :: : End of Service Life :Rev Tx)
• D-Link DIR-905L :: (Non-US :: End of Service Life)
• D-Link ShareCenter (US :: End of Service Life :: LINK)
  

Affected Devices

Recommendation for End of Support /End of Life Products

  
From time to time, D-Link will decide that some of its products have reached End of Support ("EOS") / End of Life (“EOL”). D-Link may choose to EOS/EOL a product due to the evolution of technology, market demands, new innovations, product efficiencies based on the latest technologies, or the product's maturity over time, which necessitates replacement with functionally superior technology.

For US Consumer

     
If a product has reached End of Support ("EOS") / End of Life ("EOL"), there is usually no further extended support or development for it.

Typically for these products, D-Link will be unable to resolve device or firmware issues since all development and customer support has ceased. 

D-Link strongly recommends that this product be retired and cautions that any further use of this product may be a risk to devices connected to it. If US consumers continue to use these devices against D-Link's recommendation, please ensure the device has the most recent firmware, update its unique password frequently to access its web-configuration, and always enable WIFI encryption with a unique password.