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Actively exploited

CVE-2019-17621 D-Link DIR-859 Router Command Execution Vulnerability

D-Link DIR-859 router contains a command execution vulnerability in the UPnP endpoint URL, /gena.cgi. Exploitation allows an unauthenticated remote attacker to execute system commands as root by sending a specially crafted HTTP SUBSCRIBE request to the UPnP service when connecting to the local network.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 29 Jun 2023.
  • Rated Critical severity (CVSS 9.8, scored by CISA).
  • This product type is often exposed to the internet, which is where attackers scan for it first.
  • It has been in the catalogue for 1,226 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

The UPnP endpoint URL /gena.cgi in the D-Link DIR-859 Wi-Fi router 1.05 and 1.06B01 Beta01 allows an Unauthenticated remote attacker to execute system commands as root, by sending a specially crafted HTTP SUBSCRIBE request to the UPnP service when connecting to the local network.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for D-Link DIR-859 Router. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply updates per vendor instructions or discontinue use of the product if updates are unavailable.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 20 Jul 2023 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited D-Link Flaws

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CVE-2025-29635D-Link DIR-823X Command Injection VulnerabilityAdded 24 Apr 2026CVE-2022-37055D-Link Routers Buffer Overflow VulnerabilityAdded 8 Dec 2025CVE-2020-25078D-Link DCS-2530L and DCS-2670L Devices Unspecified VulnerabilityAdded 5 Aug 2025CVE-2020-25079D-Link DCS-2530L and DCS-2670L Command Injection VulnerabilityAdded 5 Aug 2025CVE-2022-40799D-Link DNR-322L Download of Code Without Integrity Check VulnerabilityAdded 5 Aug 2025CVE-2024-0769 D-Link DIR-859 Router Path Traversal VulnerabilityAdded 25 Jun 2025

All 26 exploited D-Link vulnerabilities

Not Sure If You Are Exposed?

Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2019-17621 and every other exploited flaw on the list.

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2019-17621
  3. CVE record: CVE-2019-17621
  4. FIRST EPSS
  5. supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10147
  6. ftc.gov/system/files/documents/cases/dlink_proposed_order_and_judgment_7-2-19.pdf
  7. dlink.com/en/security-bulletin
  8. supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10146
  9. medium.com/%40s1kr10s/d-link-dir-859-rce-unautenticated-cve-2019-17621-en-d94b47a15104
  10. medium.com/%40s1kr10s/d-link-dir-859-rce-unautenticated-cve-2019-17621-es-fad716629ff9
  11. packetstormsecurity.com/files/156054/D-Link-DIR-859-Unauthenticated-Remote-Command-Execution.html