Weakness (CWE)
CWE-434: Unrestricted Upload of File with Dangerous Type
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
How to prevent it (8 mitigations)
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Architecture and Design
Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.[REF-422] [REF-423]
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Architecture and Design
When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
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Architecture and Design
Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically. [REF-423]
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Implementation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
For example, limiting filenames to alphanumeric characters can help to restrict the introduction of unintended file extensions.
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Architecture and Design
Define a very limited set of allowable extensions and only generate filenames that end in these extensions. Consider the possibility of XSS (CWE-79) before allowing .html or .htm file types.
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Implementation
Ensure that only one extension is used in the filename. Some web servers, including some versions of Apache, may process files based on inner extensions so that "filename.php.gif" is fed to the PHP interpreter.[REF-422] [REF-423]
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Implementation
When running on a web server that supports case-insensitive filenames, perform case-insensitive evaluations of the extensions that are provided.
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Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Source: MITRE CWE-434
14 results · Clear filters · Feed
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Critical 9.3
Adobe Commerce | Unrestricted Upload of File with Dangerous Type (CWE-434)
Adobe Commerce is affected by an Unrestricted Upload of File with Dangerous Type vulnerability that could result in arbitrary code execution in the context of the current user, potentially gaining elevated access or control over the victim's account or sessio…
KEV Oct 27, 2026 -
Critical 10.0
Joomla Extension - balbooa.com - Unauthenticated file upload in Balbooa Forms extension < 2.4.1
Joomla Extension - balbooa.com - Unauthenticated file upload in Balbooa Forms extension < 2.4.1 - The Joomla extension Balbooa Forms is vulnerable to an unauthenticated arbitrary file upload that allows uploading executable files and leads to full RCE.
KEV Jul 10, 2026 -
Critical 10.0
Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0
Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0 - The Joomla extension Page Builder CK is vulnerable to an unauthenticated arbitrary file upload that allows uploading executable files and leads to full RCE.
KEV Jul 7, 2026 -
Critical 10.0
Joomla Extension - joomshaper.com - Remote Code Execution in SP Pagebuilder extension for Joomla < 6.6.2
A vulnerability in SP Page Builder for Joomla allows unauthenticated users to upload arbitrary files, ultimately resulting in the upload and execution of PHP code.
KEV Jul 7, 2026 -
Critical 10.0
Joomla Extension - icagenda.com - Remote Code Execution in iCaganda extension for Joomla < 4.0.8/3.9.15
A vulnerability in the iCagenda extension for Joomla allows the upload of arbitrary files in the file attachment feature, ultimately resulting in PHP code upload and execution.
KEV Jul 10, 2026 -
Critical 10.0
Upload Arbitrary Files
Successful exploitation of the vulnerability could allow an unauthenticated attacker to upload arbitrary files to any location on the mail server, potentially enabling remote code execution.
KEV Jan 26, 2026 -
Critical 10.0
Missing Authorization check in SAP NetWeaver (Visual Composer development server)
SAP NetWeaver Visual Composer Metadata Uploader is not protected with a proper authorization, allowing unauthenticated agent to upload potentially malicious executable binaries that could severely harm the host system. This could significantly affect the conf…
KEV Apr 29, 2025 -
Critical 9.9
Advantive VeraCore before 2024.4.2.1 allows remote authenticated users to upload files to unintended folders (e.g., one…
KEV Mar 10, 2025 -
Critical 9.8
In Cleo Harmony before 5.8.0.21, VLTrader before 5.8.0.21, and LexiCom before 5.8.0.21, there is an unrestricted file u…
KEV Dec 13, 2024 -
Critical 9.8
Arbitrary file upload vulnerability in FatPipe software
A vulnerability in the web management interface of FatPipe WARP, IPVPN, and MPVPN software prior to versions 10.1.2r60p92 and 10.2.2r44p1 allows a remote, unauthenticated attacker to upload a file to any location on the filesystem. The FatPipe advisory identi…
KEV Jan 10, 2022 -
Critical 10.0
The File Manager (wp-file-manager) plugin before 6.9 for WordPress allows remote attackers to upload and execute arbitr…
KEV Nov 3, 2021 -
Critical 9.8
Adobe ColdFusion versions July 12 release (2018.0.0.310739), Update 6 and earlier, and Update 14 and earlier have an un…
KEV Nov 3, 2021 -
Critical 9.8
Progress Telerik UI for ASP.NET AJAX before R2 2017 SP2 does not properly restrict user input to RadAsyncUpload, which …
KEV Jan 26, 2023 -
Critical 9.8
Improper Input Validation in Apache ActiveMQ
The Fileserver web application in Apache ActiveMQ 5.x before 5.14.0 allows remote attackers to upload and execute arbitrary files via an HTTP PUT followed by an HTTP MOVE request.
KEV Feb 10, 2022