Cyber Resilience

CVE-2019-17621

RCE in Dlink Dir-859 Firmware ≤ 1.05b03

CISA KEVActive ExploitationEUVD ExploitedPublic PoCRCECommand Injection
Published
30 December 2019
Modified
07 November 2025
KEV Added
29 June 2023
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.90 99.8th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2019-17621 is a critical-severity OS Command Injection (CWE-78) vulnerability in Dlink Dir-859 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 0.2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

The vulnerability is an OS command injection flaw (CWE-78) affecting the UPnP service on D-Link DIR-859 Wi-Fi routers running firmware versions 1.05 and 1.06B01 Beta01. Specifically, the /gena.cgi endpoint accepts unauthenticated HTTP SUBSCRIBE requests that can be manipulated to execute arbitrary system commands with root privileges.

An attacker with network adjacency to the device can exploit the issue remotely without authentication or user interaction by crafting a malicious SUBSCRIBE request to the UPnP service. Successful exploitation grants full root-level control over the router, enabling arbitrary command execution, configuration changes, or further lateral movement within the local network. The flaw carries a CVSS 3.1 base score of 9.8.

D-Link has published security advisories SAP10146 and SAP10147 addressing the affected router models. Public proof-of-concept code demonstrating unauthenticated remote command execution has been released via Packet Storm and technical write-ups.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

to the local network.

CWE(s)
KEV Date Added
29 June 2023

Related Threats

MITRE ATT&CK Enterprise Techniques

T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
T1059.003 Windows Command Shell Execution
Adversaries may abuse the Windows command shell for execution.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2018-6530Same product: Dlink Dir-865Lboth on KEV
CVE-2016-11021Same vendor: Dlinkboth on KEV
CVE-2019-20500Same vendor: Dlinkboth on KEV
CVE-2022-26258Same vendor: Dlinkboth on KEV
CVE-2019-16920Same vendor: Dlinkboth on KEV
CVE-2020-9377Same vendor: Dlinkboth on KEV
CVE-2019-16057Same vendor: Dlinkboth on KEV
CVE-2021-45382Same vendor: Dlinkboth on KEV
CVE-2023-25280Same vendor: Dlinkboth on KEV
CVE-2020-25506Same vendor: Dlinkboth on KEV

Affected Assets

dlink
dir-859 firmware
1.06b01 · ≤ 1.05b03
dlink
dir-822 firmware
≤ 2.03b01 · ≤ 3.12b04
dlink
dir-823 firmware
1.00b06 · ≤ 1.00b06
dlink
dir-865l firmware
≤ 1.07b01
dlink
dir-868l firmware
≤ 1.12b04 · ≤ 2.05b02
dlink
dir-869 firmware
1.03b02 · ≤ 1.03b02
dlink
dir-880l firmware
≤ 1.08b04
dlink
dir-890l firmware
1.11b01 · ≤ 1.11b01
dlink
dir-890r firmware
1.11b01 · ≤ 1.11b01
dlink
dir-885l firmware
≤ 1.12b05
+4 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.2.5
  • V1.2.8
  • V15.2.5

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-78

Platform-independent apps typically execute inside a managed runtime or sandbox that restricts direct OS command execution, reducing the ability to exploit OS command injection.

addresses: CWE-78

Validates inputs to block special elements that would alter OS command execution.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.

PR.PS-02 partial match
prevents

Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.

References