CVE-2019-16920Known exploitationPublic exploitNetwork attack vector

Unauthenticated root execution via newline command injection

Published Sep 27, 2019 · Updated Oct 21, 2025

Command injection in D-Link routers' ping_test CGI allows remote attackers to execute root commands via crafted HTTP requests. The /apply_sec.cgi handler continues dispatching actions without successful authentication, and ping_test passes newline-containing ping_ipaddr input into command execution without neutralizing the command separator. Access to the router's web interface is sufficient without credentials; injected commands run as root, enabling password retrieval and backdoor installation.

CVSS severity9.8
Critical
EPSS probability100.00%
Next 30 days · Nov 1, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in D-Link routers' ping_test CGI allows remote attackers to execute root commands via crafted HTTP requests. The /apply_sec.cgi handler continues dispatching actions without successful authentication, and ping_test passes newline-containing ping_ipaddr input into command execution without neutralizing the command separator. Access to the router's web interface is sufficient without credentials; injected commands run as root, enabling password retrieval and backdoor installation.

The record

CVE
CVE-2019-16920
Published
Sep 27, 2019
Updated
Oct 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-78, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 27, 2019CVE publishedPublication date reported by the CVE source.
  2. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0CERT/CCAV:N/AC:L/Au:N/C:C/I:C/A:C
9.0CERT/CCAV:N/AC:L/Au:N/C:C/I:C/A:C/E:POC/RL:U/RC:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsShadowserver observations through Sep 28, 2026. Gaps indicate unavailable data.
Sep 22, 2026Sep 28, 2026
View daily counts
Reporting dayUnique IPs
Sep 22, 202610
Sep 23, 20263
Sep 24, 202615
Sep 25, 202617
Sep 26, 20264
Sep 27, 202618
Sep 28, 20269
Latest reporting daySep 28, 2026
Latest daily unique IPs9
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Unix Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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