CVE-2020-20287Public exploitNetwork attack vector

Unauthenticated code execution via unsafe image upload

Published Feb 1, 2021 · Updated Aug 4, 2024

Unrestricted file upload in YCCMS 3.3 allows remote attackers to execute arbitrary code through the image-upload interface. The xhUp function incorrectly evaluates request parameters and accepts a dangerous uploaded file that the server can execute as code. No authentication or user interaction is required, and successful exploitation runs attacker-controlled code in the web application's server context.

CVSS severity9.8
Critical
EPSS probability2.83%
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 YCCMS 3.3 allows remote attackers to execute arbitrary code through the image-upload interface. The xhUp function incorrectly evaluates request parameters and accepts a dangerous uploaded file that the server can execute as code. No authentication or user interaction is required, and successful exploitation runs attacker-controlled code in the web application's server context.

The record

CVE
CVE-2020-20287
Published
Feb 1, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS: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.

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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 exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1190Exploit Public-Facing Application

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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