How to fix CVE-2021-47888?

Within 24 hours: Inventory all Textpattern installations and identify those running version 4.8.3 or earlier; disable file upload functionality if business operations permit. Within 7 days: Upgrade to version 4.8.4 or later if available, or migrate to an alternative CMS platform; implement WAF rules to block suspicious file uploads. Within 30 days: Complete migration away from affected versions; conduct forensic audit of upload directories and logs for indicators of compromise; implement file type validation and execution prevention controls.

Is PHP affected by CVE-2021-47888?

Textpattern CMS versions 4.8.3 and earlier contain a critical file upload vulnerability that allows attackers to upload and execute malicious files, potentially compromising web applications and hosted data.

CVE-2021-47888

HIGH

2026-01-23 [email protected]

8.8

CVSS 3.1

CVSS Vector

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

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 26, 2026 - 15:03 vuln.today

Public exploit code

CVE Published

Jan 23, 2026 - 17:15 nvd

HIGH 8.8

Description

Textpattern versions prior to 4.8.3 contain an authenticated remote code execution vulnerability that allows logged-in users to upload malicious PHP files. Attackers can upload a PHP file with a shell command execution payload and execute arbitrary commands by accessing the uploaded file through a specific URL parameter.

Analysis

Textpattern versions up to 4.8.3 is affected by unrestricted upload of file with dangerous type (CVSS 8.8).

Technical Context

This vulnerability (CWE-434: Unrestricted Upload of File with Dangerous Type) exists in the a specific URL component. Textpattern versions prior to 4.8.3 contain an authenticated remote code execution vulnerability that allows logged-in users to upload malicious PHP files. Attackers can upload a PHP file with a shell command execution payload and execute arbitrary commands by accessing the uploaded file through a specific URL parameter.

Affected Products

Product: Textpattern. Versions: up to 4.8.3. Component: a specific URL.

Remediation

Monitor vendor advisories for a patch. Validate file types by content. Store uploads outside web root. Restrict network access to the affected service where possible.

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +0.5

CVSS: +44

POC: +20

CVE-2021-47888 vulnerability details – vuln.today

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CVE-2021-47888

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CVE-2021-47888

CVSS Vector

Lifecycle Timeline

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Description

Analysis

Technical Context

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External POC / Exploit Code