CVE-2020-21861Public exploitNetwork attack vector

Authenticated code execution via dangerous file upload

Published Jul 6, 2023 · Updated Nov 21, 2024

Unrestricted file upload in DuxCMS 2.1 allows remote authenticated users to execute arbitrary PHP code through AdminUpload/upload. The endpoint accepts a dangerous PHP file and makes its contents web-executable, although the public report does not identify the exact failed validation. A low-privileged account can run code with the web server's permissions, affecting hosted data and service operation.

CVSS severity8.8
High
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in DuxCMS 2.1 allows remote authenticated users to execute arbitrary PHP code through AdminUpload/upload. The endpoint accepts a dangerous PHP file and makes its contents web-executable, although the public report does not identify the exact failed validation. A low-privileged account can run code with the web server's permissions, affecting hosted data and service operation.

The record

CVE
CVE-2020-21861
Published
Jul 6, 2023
Updated
Nov 21, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, CAPEC-1, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 6, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 21, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
CAPEC-1Accessing Functionality Not Properly Constrained by ACLs
T1505.003Server Software Component: Web Shell

Public exploit references

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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