Cyber Resilience

CVE-2021-47903

HighPublic PoCRCE

Published: 23 January 2026

Published
23 January 2026
Modified
15 April 2026
KEV Added
Patch
CVSS Score v4 8.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0145 70.0th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2021-47903 is a high-severity OS Command Injection (CWE-78) vulnerability in Litespeedtech (inferred from references). Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 30.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Deeper analysis

LiteSpeed Web Server Enterprise version 5.4.11 suffers from an authenticated command injection vulnerability in its external app configuration interface. The flaw allows attackers to inject shell commands through the 'Command' parameter within the server configuration, facilitating remote code execution via path traversal and bash command injection. This issue is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command) and carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Authenticated administrators with access to the configuration interface can exploit this vulnerability remotely over the network with low complexity and no user interaction required. Exploitation enables the execution of arbitrary shell commands on the affected server, granting high-impact control over confidentiality, integrity, and availability, potentially leading to full system compromise.

Advisories and resources include a proof-of-concept exploit published on Exploit-DB (ID 49523) and a detailed advisory from Vulncheck on the LiteSpeed Web Server Enterprise command injection vulnerability. References to LiteSpeed Technologies' official website and products page are available, though specific patch or mitigation guidance is not detailed in the provided information.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability details

LiteSpeed Web Server Enterprise 5.4.11 contains an authenticated command injection vulnerability in the external app configuration interface. Authenticated administrators can inject shell commands through the 'Command' parameter in the server configuration, allowing remote code execution via path traversal and bash…

more

command injection.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
Why these techniques?

CVE-2021-47903 is a command injection vulnerability in a public-facing web server configuration interface (T1190: Exploit Public-Facing Application), enabling remote code execution via bash shell commands (T1059.004: Unix Shell).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2018-25115Shared CWE-78
CVE-2025-24382Shared CWE-78
CVE-2026-29058Shared CWE-78
CVE-2024-57016Shared CWE-78
CVE-2024-46484Shared CWE-78
CVE-2015-10145Shared CWE-78
CVE-2020-37002Shared CWE-78
CVE-2026-27848Shared CWE-78
CVE-2025-0356Shared CWE-78
CVE-2025-13942Shared CWE-78

Affected Assets

Litespeedtech
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly requires input validation and error handling for the 'Command' parameter in the external app configuration interface to neutralize special elements used in OS commands, preventing injection.

prevent

Mandates timely identification, reporting, and correction of the specific command injection flaw (CVE-2021-47903) in LiteSpeed Web Server.

prevent

Restricts and manages access to configuration changes, limiting authenticated administrators' ability to reach and exploit the vulnerable external app configuration interface.

References