CVE-2021-21805Network attack vector

Unauthenticated command injection via ping.php

Published Aug 5, 2021 · Updated Aug 3, 2024

OS command injection in Advantech R-SeeNet 2.4.12 allows remote attackers to execute arbitrary operating-system commands via a crafted HTTP request to ping.php. The ping.php script fails to properly validate an attacker-controlled parameter before incorporating it into a system command. No authentication or user interaction is required, so a network-reachable instance can be fully compromised in confidentiality, integrity, and availability.

CVSS severity9.8
Critical
EPSS probability69.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in Advantech R-SeeNet 2.4.12 allows remote attackers to execute arbitrary operating-system commands via a crafted HTTP request to ping.php. The ping.php script fails to properly validate an attacker-controlled parameter before incorporating it into a system command. No authentication or user interaction is required, so a network-reachable instance can be fully compromised in confidentiality, integrity, and availability.

The record

CVE
CVE-2021-21805
Published
Aug 5, 2021
Updated
Aug 3, 2024
Vendor
Advantech
Product
R-SeeNet
Classifications
CWE-78, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Advantech R-SeeNet 2.4.12 (20.10.2020)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Advantech · R-SeeNetversion=Advantech R-SeeNet 2.4.12 (20.10.2020)

Published CVSS scores

9.8Cisco TalosCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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