Malicious File Upload
Malicious file upload attacks exploit insufficient validation when web applications accept user-provided files.
How It Works
Malicious file upload attacks exploit insufficient validation when web applications accept user-provided files. The attacker uploads a file containing executable code—commonly a web shell written in PHP, JSP, or ASPX—disguised to bypass basic security checks. Once uploaded to a web-accessible directory, the attacker navigates to the file's URL, triggering server-side execution and gaining remote command execution capabilities.
Attackers employ various bypass techniques to defeat weak filters. Content-Type spoofing involves manipulating HTTP headers to claim a malicious PHP file is an image. Double extensions like shell.php.jpg exploit flawed parsers that only check the final extension. Null byte injection (shell.php%00.jpg) can truncate filenames in vulnerable code. Case manipulation (.pHp, .AsP) defeats case-sensitive blacklists. Advanced attacks upload .htaccess or web.config files to reconfigure the server, enabling script execution in directories where it was previously disabled.
The typical attack flow begins with reconnaissance to locate upload functionality, followed by testing various evasion techniques until a payload successfully uploads. The attacker then accesses the uploaded web shell through a browser, passing commands via URL parameters. This establishes an interactive backdoor for further exploitation, lateral movement, and data theft.
Impact
- Remote code execution: Full command-line access to the web server with the application's privileges
- Web shell persistence: Durable backdoor survives application restarts, enabling long-term access
- Data exfiltration: Direct file system access allows theft of databases, credentials, source code, and sensitive documents
- Server compromise: Ability to install additional malware, create privileged accounts, and pivot to internal networks
- Website defacement: Modification of public-facing content to damage reputation or spread misinformation
Real-World Examples
Cisco Wireless LAN Controller (CVE-2025-20188) combined a hardcoded JWT credential with unrestricted file upload, allowing unauthenticated attackers to deploy web shells and achieve complete controller compromise. The dual vulnerability eliminated authentication barriers entirely.
WordPress plugin vulnerabilities frequently expose this attack surface. Numerous plugins have allowed arbitrary file uploads through image galleries or media managers, where attackers upload PHP shells disguised as images, then execute them to take over hosting environments.
Enterprise content management systems have suffered similar flaws where document upload features failed to validate file types properly, allowing attackers to upload executable scripts that provided administrative access to corporate intranets and sensitive business data.
Mitigation
- Whitelist permitted extensions and validate against both filename and actual file content (magic bytes/file signatures)
- Store uploads outside the webroot entirely, serving them through a handler script that prevents execution
- Disable script execution in upload directories via web server configuration (remove execute permissions)
- Rename uploaded files to random identifiers, breaking the attacker's ability to predict URLs
- Implement content scanning with antivirus/malware detection before storing files
- Enforce authentication and authorization on all upload endpoints with proper session management
- Validate file size limits to prevent resource exhaustion alongside malicious uploads
Recent CVEs (4270)
WordPress is an open publishing platform for the Web. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
projeqtor up to 11.2.0 was discovered to contain a remote code execution (RCE) vulnerability via the component /view/print.php. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
File Upload vulnerability in Byzoro Networks Smart multi-service security gateway intelligent management platform version S210, allows an attacker to obtain sensitive information via the. Rated medium severity (CVSS 6.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Authenticated arbitrary file upload in the BookingPress WordPress plugin (versions through 1.0.87) enables remote code execution by administrator-level users who can upload malicious files via the 'bookingpress_process_upload' function. Publicly available exploit code exists and EPSS places this in the 92nd percentile (8.31% probability), indicating elevated likelihood of exploitation attempts despite the high-privilege requirement. The flaw affects the free WordPress edition distributed by Repute InfoSystems.
Unrestricted Upload of File with Dangerous Type vulnerability in Themeisle Multiple Page Generator Plugin - MPG allows Upload a Web Shell to a Web Server.4.0. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An issue was discovered in SEMCMS v.4.8, allows remote attackers to execute arbitrary code, escalate privileges, and obtain sensitive information via the upload.php file. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
File Upload vulnerability in lepton v.7.1.0 allows a remote authenticated attackers to execute arbitrary code via uploading a crafted PHP file. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A vulnerability was found in SourceCodester Image Accordion Gallery App 1.0. Rated medium severity (CVSS 6.3), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Techeshta Layouts for Elementor.8. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in QuanticaLabs Chauffeur Taxi Booking System for WordPress.2. Rated critical severity (CVSS 10.0), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in biplob018 Shortcode Addons.2.5. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Epss exploitation probability 48.7% and no vendor patch available.
A vulnerability classified as critical was found in YouDianCMS up to 9.5.12. Rated medium severity (CVSS 4.7), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Salon Booking System Salon booking system.5. Rated critical severity (CVSS 10.0), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in CubeWP CubeWP - All-in-One Dynamic Content Framework.1.12. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An issue in Mblog Blog system v.3.5.0 allows an attacker to execute arbitrary code via a crafted file to the theme management feature. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Tumult Inc. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Jordy Meow AI Engine: ChatGPT Chatbot.1.4. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
ZITADEL users can upload their own avatar image and various image types are allowed. Rated high severity (CVSS 8.7), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in WappPress Team WappPress.0.3. Rated critical severity (CVSS 10.0), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A vulnerability exists in the stb-language file handling that affects the RTU500 series product versions listed below. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A vulnerability exists in the stb-language file handling that affects the RTU500 series product versions listed below. Rated high severity (CVSS 8.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A vulnerability was found in SourceCodester Music Gallery Site 1.0. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Elementor.Com Elementor Website Builder.3.0 through 3.18.1. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and EPSS exploitation probability 90.8%.
Unrestricted Upload of File with Dangerous Type vulnerability in Trustindex.Io Widgets for Google Reviews.0.2. Rated high severity (CVSS 8.0), this vulnerability is remotely exploitable. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in WEN Solutions WP Child Theme Generator.0.9. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and EPSS exploitation probability 13.0%.
Unrestricted Upload of File with Dangerous Type vulnerability in Terry Lin WP Githuber MD.16.2. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Zachary Segal CataBlog.7.0. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in ThemeFusion Avada.11.1. Rated high severity (CVSS 8.5), this vulnerability is remotely exploitable. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Artbees JupiterX Core.3.5. Rated critical severity (CVSS 9.0), this vulnerability is remotely exploitable, no authentication required. Epss exploitation probability 22.9% and no vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Julien Crego Manager for Icomoon.0. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in mndpsingh287 Theme Editor.7.1. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in OnTheGoSystems Types.4.17. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in MainWP MainWP File Uploader Extension.1. Rated critical severity (CVSS 10.0), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in WebToffee Product Import Export for WooCommerce.4.1. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
File Upload vulnerability in lepton v.7.1.0 allows a remote authenticated attackers to execute arbitrary code via uploading a crafted PHP file to the save.php and config.php component. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
phpMyFAQ is an open source FAQ web application for PHP 8.1+ and MySQL, PostgreSQL and other databases. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available.
The CRM platform Twenty version 0.3.0 is vulnerable to SSRF via file upload. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
The CRM platform Twenty is vulnerable to stored cross site scripting via file upload in version 0.3.0. Rated high severity (CVSS 7.6), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
This vulnerability allows remote attackers to traverse paths via file upload on the affected LG LED Assistant. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A vulnerability classified as critical was found in SourceCodester Simple File Manager 1.0. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Arbitrary File Upload vulnerability in VvvebJs before version 1.7.5, allows unauthenticated remote attackers to execute arbitrary code and obtain sensitive information via the sanitizeFileName. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
File Upload vulnerability in magicflue v.7.0 and before allows a remote attacker to execute arbitrary code via a crafted request to the messageid parameter of the mail/mailupdate.jsp endpoint. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Grav is an open-source, flat-file content management system. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available.
A Cross-Site Request Forgery (CSRF) vulnerability in gradio-app/gradio allows attackers to upload multiple large files to a victim's system if they are running Gradio locally. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
Unrestricted Upload of File with Dangerous Type vulnerability in Gesundheit Bewegt GmbH Zippy.6.9. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A vulnerability classified as critical has been found in SourceCodester Complete E-Commerce Site 1.0. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
In MISP before 2.4.187, add_misp_export in app/Controller/EventsController.php does not properly check for a valid file upload. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Unrestricted File Upload vulnerability could allow attackers to upload malicious files that can be executed on the server.
An issue was discovered in osCommerce v4, allows local attackers to bypass file upload restrictions and execute arbitrary code via administrator profile photo upload feature. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
A vulnerability was found in SourceCodester Online Discussion Forum Site 1.0. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
The Management App for WooCommerce - Order notifications, Order management, Lead management, Uptime Monitoring plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Themefic Tourfic tourfic.11.15. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An Unrestricted Upload of File vulnerability has been found on Cegid Meta4 HR, that allows an attacker to upload malicios files to the server via '/config/espanol/update_password.jsp' file. Rated critical severity (CVSS 9.0), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
A vulnerability was found in SourceCodester File Manager App 1.0. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
File upload restriction evasion vulnerability in AMSS++ version 4.31. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Pie Register.8.3.1. Rated critical severity (CVSS 10.0), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A vulnerability was found in PandaXGO PandaX up to 20240310. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A vulnerability, which was classified as critical, has been found in 74CMS 3.28.0. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A vulnerability classified as critical has been found in MAGESH-K21 Online-College-Event-Hall-Reservation-System 1.0. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A vulnerability was found in MAGESH-K21 Online-College-Event-Hall-Reservation-System 1.0. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Unrestricted File Upload vulnerability in Greek Universities Network Open eClass v.3.15 and earlier allows attackers to run arbitrary code via upload of crafted file to certbadge.php endpoint. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
greykite v1.0.0 was discovered to contain an arbitrary file upload vulnerability in the load_obj function at /templates/pickle_utils.py. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
zenml v0.55.4 was discovered to contain an arbitrary file upload vulnerability in the load function at /materializers/cloudpickle_materializer.py. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Airflow-Diagrams v2.1.0 was discovered to contain an arbitrary file upload vulnerability in the unsafe_load function at cli.py. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Webedition CMS 9.2.2.0 has a File upload vulnerability via /webEdition/we_cmd.php. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A path traversal vulnerability exists in Arcserve Unified Data Protection 9.2 and 8.1 in edge-app-base-webui.jar!com.ca.arcserve.edge.app.base.ui.server.servlet.ImportNodeServlet. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
The Otter Blocks - Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE PRO plugin for WordPress is vulnerable to Stored Cross-Site Scripting via file upload form, which allows SVG uploads, in. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The Brizy - Page Builder plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the storeImages function in all versions up to, and including, 2.4.40. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. This Unrestricted File Upload vulnerability could allow attackers to upload malicious files that can be executed on the server.
A vulnerability, which was classified as critical, was found in Gacjie Server up to 1.0. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Unrestricted file upload vulnerability in CMS Made Simple, affecting version 2.2.14. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A vulnerability was found in SourceCodester Employee Management System 1.0. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An unauthenticated remote attacker can upload a arbitrary script file due to improper input validation. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
SOY CMS is an open source CMS (content management system) that allows you to build blogs and online shops. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. This OS Command Injection vulnerability could allow attackers to execute arbitrary operating system commands on the host.
A vulnerability was found in keerti1924 Online-Book-Store-Website 1.0. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The Booster Elite for WooCommerce plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the wc_add_new_product() function in all versions up to, and. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Epss exploitation probability 10.5% and no vendor patch available.
File Upload vulnerability in Byzro Network Smart s42 Management Platform v.S42 allows a local attacker to execute arbitrary code via the useratte/userattestation.php component. Rated high severity (CVSS 7.7), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
A vulnerability in the file upload functionality of Cisco AppDynamics Controller could allow an authenticated, remote attacker to conduct directory traversal attacks on an affected device. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A vulnerability classified as critical has been found in SourceCodester Online Mobile Management Store 1.0. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
File Upload vulnerability in Petrol Pump Mangement Software v.1.0 allows an attacker to execute arbitrary code via a crafted payload to the email Image parameter in the profile.php component. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Bagisto v1.5.1 is vulnerable for Cross site scripting(XSS) via png file upload vulnerability in product review option. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A vulnerability was found in SourceCodester Petrol Pump Management Software 1.0. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A vulnerability was found in SourceCodester Petrol Pump Management Software 1.0. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Enabling Simple Ajax Uploader plugin included in Laragon open-source software allows for a remote code execution (RCE) attack via an improper input validation in a file_upload.php file which serves. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Unrestricted Upload of File with Dangerous Type vulnerability in Mollie Mollie Payments for WooCommerce.3.11. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
The Avada | Website Builder For WordPress & WooCommerce theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the ajax_import_options() function in all. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
F-logic DataCube3 v1.0 is vulnerable to unrestricted file upload, which could allow an authenticated malicious actor to upload a file of dangerous type by manipulating the filename extension. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
An Unrestricted File Upload vulnerability in CodeAstro Membership Management System in PHP v.1.0 allows a remote attacker to execute arbitrary code via upload of a crafted php file in the. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Unrestricted Upload of File with Dangerous Type in freescout-helpdesk/freescout. Rated medium severity (CVSS 4.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
In the module "Product Catalog (CSV, Excel) Import" (simpleimportproduct) <= 6.7.0 from MyPrestaModules for PrestaShop, a guest can upload files with extensions .php. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A vulnerability was found in Ctcms 2.1.2. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
A vulnerability, which was classified as critical, was found in osuuu LightPicture up to 1.2.2. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Quick Facts
- Typical Severity
- HIGH
- Category
- web
- Total CVEs
- 4270