CVE-2026-57578

DotVVM is an open source MVVM framework for web applications. Prior to 4.2.11, 4.3.15, and 5.0.0-preview09-final, AuthorizeActionFilter performs no authorization because its explicit ICommandActionFilter.OnCommandExecutingAsync, IViewModelActionFilter.OnViewModelCreatedAsync, and IPresenterActionFilter.OnPresenterExecutingAsync implementations return completed tasks instead of invoking the corresponding checks. Applications relying on this filter can therefore expose protected commands, view models, or presenters to unauthorized requests without any special bypass technique. AuthorizeAttribute correctly implements the same interfaces and can be used as a workaround. This issue is fixed in versions 4.2.11, 4.3.15, and 5.0.0-preview09-final.

DotVVM is an open source MVVM framework for web applications. Prior to 4.2.11, 4.3.15, and 5.0.0-preview09-final, AuthorizeActionFilter performs no authorization because its explicit ICommandActionFilter.OnCommandExecutingAsync, IViewModelActionFilter.OnViewModelCreatedAsync, and IPresenterActionFilter.OnPresenterExecutingAsync implementations return completed tasks instead of invoking the corresponding checks. Applications relying on this filter can therefore expose protected commands, view models, or presenters to unauthorized requests without any special bypass technique. AuthorizeAttribute correctly implements the same interfaces and can be used as a workaround. This issue is fixed in versions 4.2.11, 4.3.15, and 5.0.0-preview09-final.

Impact

All users of the AuthorizeActionFilter class are affected. The AuthorizeActionFilter simply does nothing, no “hacking” is needed to bypass the filter.

Patches

DotVVM 4.3.15, 4.2.11 and 5.0.0-preview09 fix this.

Workarounds

As a workaround, you can use the AuthorizeAttribute instead. It implements the same interfaces (correctly). Note that is it deprecated for unrelated reasons, feel free to suppress the warning when using it as action filter.

DotVVM is an open source MVVM framework for web applications. Prior to 4.2.11, 4.3.15, and 5.0.0-preview09-final, AuthorizeActionFilter performs no authorization because its explicit ICommandActionFilter.OnCommandExecutingAsync, IViewModelActionFilter.OnViewModelCreatedAsync, and IPresenterActionFilter.OnPresenterExecutingAsync implementations return completed tasks instead of invoking the corresponding checks. Applications relying on this filter can therefore expose protected commands, view models, or presenters to unauthorized requests without any special bypass technique. AuthorizeAttribute correctly implements the same interfaces and can be used as a workaround. This issue is fixed in versions 4.2.11, 4.3.15, and 5.0.0-preview09-final.

DotVVM is an open source MVVM framework for web applications. Prior to 4.2.11, 4.3.15, and 5.0.0-preview09-final, AuthorizeActionFilter performs no authorization because its explicit ICommandActionFilter.OnCommandExecutingAsync, IViewModelActionFilter.OnViewModelCreatedAsync, and IPresenterActionFilter.OnPresenterExecutingAsync implementations return completed tasks instead of invoking the corresponding checks. Applications relying on this filter can therefore expose protected commands, view models, or presenters to unauthorized requests without any special bypass technique. AuthorizeAttribute correctly implements the same interfaces and can be used as a workaround. This issue is fixed in versions 4.2.11, 4.3.15, and 5.0.0-preview09-final.