What is the CVSS score of CVE-2021-47753?

CVE-2021-47753 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Which versions of PHP are affected by CVE-2021-47753?

Organizations using phpKF CMS 3.00 Beta y6 face critical risk from CVE-2021-47753, a unrestricted file upload vulnerability rated CVSS 9.8.

Is there a public PoC exploit available for CVE-2021-47753?

Yes, a public proof-of-concept exploit is available for CVE-2021-47753. Prioritise patching immediately. EPSS: 0.3%.

How to fix or mitigate CVE-2021-47753?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. Review file handling controls and restrict upload directories.

PHP CVE-2021-47753

CRITICAL

Unrestricted Upload of File with Dangerous Type (CWE-434)

2026-01-15 disclosure@vulncheck.com

PHP Cms

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

PoC Detected

Jan 23, 2026 - 18:31 vuln.today

Public exploit code

CVE Published

Jan 15, 2026 - 16:16 nvd

CRITICAL 9.8

DescriptionCVE.org

phpKF CMS 3.00 Beta y6 contains an unauthenticated file upload vulnerability that allows remote attackers to execute arbitrary code by bypassing file extension checks. Attackers can upload a PHP file disguised as a PNG, rename it, and execute system commands through a crafted web shell parameter.

AnalysisAI

phpKF CMS 3.00 Beta allows unauthenticated PHP file upload by disguising it as a PNG, then renaming it for execution. PoC available.

Technical ContextAI

File upload check can be bypassed by uploading PHP as PNG then renaming (CWE-434).

RemediationAI

Do not use this software in production.

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CVE-2021-47753 vulnerability details – vuln.today

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PHP CVE-2021-47753

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

RemediationAI

More from same product – last 7 days

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External POC / Exploit Code