IoTSharp BlobStorageController BlobStorageController.cs _blob.WriteFileAsync formFile path traversal

Summaryinfo

A vulnerability was found in IoTSharp and classified as critical. The affected element is the function _blob.WriteFileAsync of the file BlobStorageController.cs of the component BlobStorageController. Executing a manipulation of the argument formFile can lead to path traversal. The identification of this vulnerability is CVE-2026-71262. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in IoTSharp (the affected version is unknown) and classified as critical. This vulnerability affects the function _blob.WriteFileAsync of the file BlobStorageController.cs of the component BlobStorageController. The manipulation of the argument formFile with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

IoTSharp BlobStorageController.cs lacks the [Authorize] attribute applied to every other controller in the application (DevicesController, CustomersController, TenantsController, etc.), and no global authorization FallbackPolicy is configured in Startup.cs, leaving its Upload/Download/List/Modify/Delete endpoints reachable by unauthenticated remote attackers. The path/filename parameters passed to these endpoints (e.g. `_blob.WriteFileAsync($"{path}/{formFile.FileName}", ...)`) are used without sanitization, enabling path traversal that allows writing, reading, modifying, and deleting arbitrary files outside the intended blob storage directory, including web-accessible paths that can be leveraged for remote code execution via webshell upload.

The advisory is available at github.com. This vulnerability was named CVE-2026-71262 since 08/05/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/05/2026). This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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• IoTSharp

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CPE 2.2info

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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