CVE-2021-20850Network attack vector

Unauthenticated OS command execution via XMLRPC API

Published Nov 24, 2021 · Updated Aug 3, 2024

OS command injection in PowerCMS 5.19 and earlier allows remote attackers to execute arbitrary commands through the XMLRPC API. Neither Alfasado nor JVN discloses which XMLRPC method or parameter reaches command execution. Exploitation requires network access to the enabled XMLRPC application and grants command execution with the web application process's privileges.

CVSS severity9.8
Critical
EPSS probability1.49%
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 PowerCMS 5.19 and earlier allows remote attackers to execute arbitrary commands through the XMLRPC API. Neither Alfasado nor JVN discloses which XMLRPC method or parameter reaches command execution. Exploitation requires network access to the enabled XMLRPC application and grants command execution with the web application process's privileges.

The record

CVE
CVE-2021-20850
Published
Nov 24, 2021
Updated
Aug 3, 2024
Vendor
Alfasado Inc.
Product
PowerCMS
Classifications
CWE-78, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 24, 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=PowerCMS 5.19 and earlier, PowerCMS 4.49 and earlier, PowerCMS 3.295 and earlier, PowerCMS 2 Series (End-of-Life, EOL)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Alfasado Inc. · PowerCMSversion=PowerCMS 5.19 and earlier, PowerCMS 4.49 and earlier, PowerCMS 3.295 and earlier, PowerCMS 2 Series (End-of-Life, EOL)

Published CVSS scores

9.8JPCERT/CC and IPA Japan Vulnerability NotesCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:P/I:P/A:P
7.5JPCERT/CC and IPA Japan Vulnerability NotesAV:N/AC:L/Au:N/C:P/I:P/A:P

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')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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