diff --git a/_articles/faq/chromium-142-local-network-access-issue.md b/_articles/faq/chromium-142-local-network-access-issue.md index e4495656..3a72607c 100644 --- a/_articles/faq/chromium-142-local-network-access-issue.md +++ b/_articles/faq/chromium-142-local-network-access-issue.md @@ -7,7 +7,7 @@ keywords: Dynamic Web TWAIN, Error Troubleshooting, CORS, unknown address space, breadcrumbText: Error message - Permission was denied for this request to access the unknown address space description: CORS unknown address space date: 2025-11-04 17:21:42 +0800 -last_modified: 2025-11-26 15:46:00 +0800 +last_modified: 2025-12-12 10:04:00 +0800 --- # Error Troubleshooting @@ -19,7 +19,7 @@ last_modified: 2025-11-26 15:46:00 +0800 ### Overview -Starting in **Chromium-based browsers v142+** (released Oct 28, 2025)—including Chrome, Edge, Brave, and Opera—Dynamsoft Web TWAIN Service may not work as expected due to new local-network security rules. +Starting in **Chromium-based browsers v142+** (released Oct 28, 2025)—including Chrome, Edge, Brave, and Opera—Dynamsoft Web TWAIN Service may not work as expected due to new **Local Network Access (LNA)** restrictions that limit requests **from public network locations to private and loopback network locations**. ### Symptoms @@ -41,6 +41,8 @@ from origin 'https://your-domain.com' has been blocked by CORS policy: Permission was denied for this request to access the `unknown` address space. ``` +This error occurs because the web page is loaded from a public network origin (for example, `https://your-domain.com`) and is attempting to connect to a loopback network location (`127.0.0.1`), which Chrome now treats as a protected local network request. + --- #### Version-Specific Behavior @@ -59,10 +61,14 @@ The observed behavior depends on Chromium browser version and Dynamic Web TWAIN ### Root Cause -Chromium 142 introduces a new [Local Network Access security policy](https://chromestatus.com/feature/5152728072060928) requirement. -Requests from web pages to loopback addresses such as `localhost` / `127.0.0.1` are blocked unless the user (or an admin policy) explicitly grants access. +Chromium 142 introduces and enforces a new [Local Network Access (LNA)](https://chromestatus.com/feature/5152728072060928) security model that restricts requests **from public network locations to private and loopback network locations**, requiring explicit user permission. + +> [!NOTE] +> For background and design rationale, see Chrome’s Developer Blog: [New permission prompt for Local Network Access](https://developer.chrome.com/blog/local-network-access). + +Under this model, **requests originating from a public network location** (such as a publicly hosted website) **to private or loopback network locations** (including localhost and 127.0.0.1) are blocked by default unless the user explicitly grants permission. -Because Dynamic Web TWAIN communicates with a local service, these restrictions can prevent normal operation. +Dynamic Web TWAIN relies on a locally installed service that listens on a loopback address. When a web application hosted on a public domain attempts to communicate with this service, Chrome categorizes the request as a **public-to-local** network request, which now requires explicit user consent. ### Resolution @@ -166,6 +172,6 @@ Here are the details: This design will be integrated in v19.3. For old versions, we can include an extra js file, which can be retrieved by contacting [support](mailto://support@dynamsoft.com). -## Other Causes +## Other Causes of Failure to Connect to the Service There are other causes of service not being connected. You can find them in [another FAQ](/_articles/faq/service-prompting-to-install-repeatedly.md).