Use a regex to filter our invalid culture codes rather than relying on the culture being installed on the operating system #19821
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…n the culture being installed on the operating system.
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Pull Request Overview
This PR improves the culture code validation in the PreviewController by replacing OS-dependent culture validation with a regex-based approach to prevent XSS attacks. The change addresses a security hardening issue where syntactically valid culture codes were being rejected unnecessarily when not installed on the operating system.
- Replaces
CultureInfo.GetCultureInfo()validation with regex pattern matching - Makes validation method internal and adds comprehensive unit tests
- Updates documentation to clarify the security-focused purpose of the validation
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| src/Umbraco.Web.BackOffice/Controllers/PreviewController.cs | Implements regex-based culture validation and updates method visibility |
| tests/Umbraco.Tests.UnitTests/Umbraco.Web.BackOffice/Controllers/PreviewControllerTests.cs | Adds comprehensive unit tests for the new validation logic |
Co-authored-by: Nuklon <[email protected]>
nikolajlauridsen
approved these changes
Aug 6, 2025
nikolajlauridsen
deleted the
v13/bugfix/support-non-framework-cultures-in-preview
branch
Contributor
|
Looking close at V16 we actually need to parse the culture info there, however, it should allow made up cultures, so I'll hold off porting this 👍 |
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Prerequisites
Addresses: #19817
Description
The linked issue flags a security hardening introduced to ensure that the culture code provided in the preview URL is valid. We did this by verifying that the culture code provided one can be used to construct a
CultureInfo. However this failed unnecessarily for culture codes that were valid syntactically but not installed on the operation system and exposed by .NET.Given we have this to prevent XSS vulnerabilities, it would seem enough to verify the culture code contains only valid characters. So that's what this PR does.
Testing
Preview a page in Umbraco and verify that the provided culture code is accepted and the preview shown.
Manipulate the culture code provided in the querystring to create an invalid one and verify that an exception is thrown.
Release
Needs to be merged/re-applied to Umbraco 16.