CVE-2026-71262: Missing Auth (CVSS 9.8)

Description

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.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0035

Probability of exploitation

0.28%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-306 Missing Authentication

References

Other References

https://github.com/IoTSharp/IoTSharp https://github.com/IoTSharp/IoTSharp/blob/master/IoTSharp/Controllers/BlobStorageController.cs

Frequently Asked Questions

What is CVE-2026-71262? +

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-71262? +

CVE-2026-71262 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0035, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-71262? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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