Cyber Resilience

CVE-2021-21805

RCE in Advantech R-Seenet 2.4.12

Public PoCHigh EPSSRCECommand Injection
Published
05 August 2021
Modified
21 November 2024
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 0.70 99.3th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2021-21805 is a critical-severity OS Command Injection (CWE-78) vulnerability in Advantech R-Seenet. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 0.7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

An OS Command Injection vulnerability exists in the ping.php script functionality of Advantech R-SeeNet v 2.4.12 (20.10.2020). A specially crafted HTTP request can lead to arbitrary OS command execution. An attacker can send a crafted HTTP request to trigger this…

more

vulnerability.

CWE(s)
CWE-78

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1190 Exploit Public-Facing Application Initial Accessconfidence: HIGH
The vulnerability is an OS command injection in a web-accessible ping.php script, directly enabling remote command execution via crafted HTTP requests to a public-facing application.
attack.mitre.org →
T1059.004 Unix Shell Executionconfidence: HIGH
Successful exploitation results in arbitrary OS command execution on the underlying Unix-like system.
attack.mitre.org →
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2023-3256Same product: Advantech R-Seenet
CVE-2023-2611Same product: Advantech R-Seenet
CVE-2023-5642Same product: Advantech R-Seenet
CVE-2021-21801Same product: Advantech R-Seenet
CVE-2024-50366Same vendor: Advantech
CVE-2024-50370Same vendor: Advantech
CVE-2024-50362Same vendor: Advantech
CVE-2024-50365Same vendor: Advantech
CVE-2024-50368Same vendor: Advantech
CVE-2024-50367Same vendor: Advantech

Affected Assets

advantech
r-seenet
2.4.12

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

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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.

SC-27 Platform-independent Applications
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.

SI-10 Information Input Validation
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.

A.8.29 Security testing in development and acceptance mostly match
detects

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

References