CWE-646
Reliance on File Name or Extension of Externally-Supplied File
VariantIncompleteLikelihood: High
Description
The product allows a file to be uploaded, but it relies on the file name or extension of the file to determine the appropriate behaviors. This could be used by attackers to cause the file to be misclassified and processed in a dangerous fashion.
An application might use the file name or extension of a user-supplied file to determine the proper course of action, such as selecting the correct process to which control should be passed, deciding what data should be made available, or what resources should be allocated. If the attacker can cause the code to misclassify the supplied file, then the wrong action could occur. For example, an attacker could supply a file that ends in a ".php.gif" extension that appears to be a GIF image, but would be processed as PHP code. In extreme cases, code execution is possible, but the attacker could also cause exhaustion of resources, denial of service, exposure of debug or system data (including application source code), or being bound to a particular server side process. This weakness may be due to a vulnerability in any of the technologies used by the web and application servers, due to misconfiguration, or resultant from another flaw in the application itself.
Hierarchy (View 1000)
Parents
Children
none
Related attack patterns (CAPEC)
CAPEC-209
CVEs mapped to this weakness (4)
| CVE | Sev | Risk | CVSS | EPSS | KEV | Published | Description |
|---|---|---|---|---|---|---|---|
| CVE-2026-45315 | Hig | 0.57 | 8.7 | 0.00 | May 15, 2026 | Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, the audio transcription upload endpoint takes the file extension from the user-supplied filename and saves the file under CACHE_DIR/audio/transcriptions/.. The /cache/{path} route serves these files via FileResponse, which sets Content-Type from the on-disk extension and emits no Content-Disposition. A verified user with the default-on chat.stt permission can upload a polyglot WAV+HTML file named pwn.html and trick any other user into opening the resulting URL — the response comes back as text/html and any embedded <script> runs in the Open WebUI origin. This vulnerability is fixed in 0.9.3. | |
| CVE-2025-58449 | Hig | 0.50 | — | 0.00 | Sep 8, 2025 | Maho is a free and open source ecommerce platform. In Maho prior to 25.9.0, an authenticated staff user with access to the `Dashboard` and `Catalog\Manage Products` permissions can create a custom option on a listing with a file input field. By allowing file uploads with a `.php` extension, the user can use the filed to upload malicious PHP files, gaining remote code execution. Version 25.9.0 fixes the issue. | |
| CVE-2026-20172 | Med | 0.28 | 4.3 | 0.00 | May 6, 2026 | A vulnerability in the Lite Agent feature of Cisco Enterprise Chat and Email (ECE) could allow an authenticated, remote attacker to conduct browser-based attacks. To exploit this vulnerability, the attacker must have valid credentials for a user account with at least the role of Agent. This vulnerability is due to inadequate validation of file contents during file upload operations. An attacker could exploit this vulnerability by uploading a file that contains malicious scripts or HTML code, which the application could make available to other users to access. A successful exploit could allow the attacker to execute the contents of that file in the browser of a user and conduct browser-based attacks. | |
| CVE-2025-41720 | Med | 0.28 | 4.3 | 0.00 | Oct 22, 2025 | A low privileged remote attacker can upload arbitrary data masked as a png file to the affected device using the webserver API because only the file extension is verified. |