How severe is CVE-2019-17621?

CVE-2019-17621 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2019-17621?

Affected package information for CVE-2019-17621 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2019-17621?

No fixed release is recorded for CVE-2019-17621 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2019-17621 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2019-17621 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2019-17621 actively exploited in the wild?

Yes. There are 8 known exploit references for CVE-2019-17621, including 7 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2019-17621?

CVE-2019-17621 has an EPSS (Exploit Prediction Scoring System) score of 89.6%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2019-17621 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2019-17621 (D-Link DIR-859 Router Command Execution Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2023-06-29. CISA required all US federal civilian agencies to remediate this vulnerability by 2023-07-20. The required action was: Apply updates per vendor instructions or discontinue use of the product if updates are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2019-17621?

CVE-2019-17621 is classified as OS Command Injection (CWE-78). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2019-17621 published, and has it been updated?

CVE-2019-17621 was published on December 30, 2019 and was last updated on October 21, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🛡️

CISA KEV · ACTIVELY EXPLOITED

CRITICAL severity

CVE-2019-17621

CRITICAL

CVE-2019-17621 is a critical-severity (CVSS 9.8) OS Command Injection vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2023-06-29) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

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…

Published

Dec 30, 2019

Updated

Oct 21, 2025

Affected

14 products

Patched

See advisory

Exploits

8 known

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2023-06-29. Federal agencies were required to remediate by 2023-07-20.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2019-17621.

EPSS Exploitation Probability

via FIRST.org ↗

89.6%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2019-17621 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).

Where this sits among everything scored

Of 395,249 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.

Description

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.

Affected Products

14 products · 21 configurations

dir-818lx firmwaredlink

all

dir-822 firmwaredlink

≤ 3.12b04

range

dir-823 firmwaredlink

≤ 1.00b06

1 version

1.00b06

dir-859 firmwaredlink

≤ 1.05b03

1 version

1.06b01

dir-865l firmwaredlink

≤ 1.07b01

range

dir-868l firmwaredlink

≤ 2.05b02

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.