CVE-2021-4436
Published: April 11, 2026
Official Description
The 3DPrint Lite WordPress plugin before 1.9.1.5 does not have any authorisation and does not check the uploaded file in its p3dlite_handle_upload AJAX action , allowing unauthenticated users to upload arbitrary file to the web server. However, there is a .htaccess, preventing the file to be accessed on Web servers such as Apache.
Risk Analysis
The 3DPrint Lite WordPress plugin before 1.9.1.5 allows unauthenticated users to upload arbitrary files due to a lack of authorization and file validation. While a .htaccess file may prevent direct web access on Apache, the vulnerability itself is critical. Its inclusion in CISA's KEV catalog confirms active exploitation, making this a severe and urgent threat.
This vulnerability is actively exploited in the wild and is listed in CISA's Known Exploited Vulnerabilities catalog, indicating a high risk of compromise.
Update the 3DPrint Lite WordPress plugin to version 1.9.1.5 or later to address the arbitrary file upload vulnerability. Ensure all file upload functionalities include robust authorization checks and strict file type validation.
Technical Analysis
CVE-2021-4436 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2021-4436 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-4436 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1