CVE-2020-21174Public exploitNetwork attack vector

Remote code execution via unrestricted image upload

Published Jun 20, 2023 · Updated Dec 10, 2024

Unrestricted file upload in liufee CMS before 2.0.8.1 allows remote attackers to execute arbitrary PHP code through crafted image suffixes. The backend user-avatar and article-thumbnail handlers accepted extension-controlled upload values without instantiating Yii UploadedFile objects, bypassing image-extension validation. The issue demonstrates the user-profile update route, while the published assessment requires no prior privileges or user interaction; uploaded PHP permits server-side command execution.

CVSS severity9.8
Critical
EPSS probability1.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Unrestricted file upload in liufee CMS before 2.0.8.1 allows remote attackers to execute arbitrary PHP code through crafted image suffixes. The backend user-avatar and article-thumbnail handlers accepted extension-controlled upload values without instantiating Yii UploadedFile objects, bypassing image-extension validation. The issue demonstrates the user-profile update route, while the published assessment requires no prior privileges or user interaction; uploaded PHP permits server-side command execution.

The record

CVE
CVE-2020-21174
Published
Jun 20, 2023
Updated
Dec 10, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1505.003, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 20, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 10, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8National Vulnerability DatabaseCVSS: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.

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 exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1505.003Web Shell
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo