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SDK 1.0.3965-prerelease, for Runtime 148 (Apr. 13, 2026)

Release notes for Microsoft Edge WebView2 Prerelease SDK, release date: April 13, 2026.

NuGet package for WebView2 SDK 1.0.3965-prerelease

For full API compatibility, this Prerelease version of the WebView2 SDK requires the WebView2 Runtime that ships with Microsoft Edge version 148.0.3965.0 or later; see Runtime 148.0.3967.48 (May 11, 2026).

Breaking change: Granular process failure reasons for the ProcessFailed event

The ProcessFailed event fires when a WebView2-associated process (such as a renderer or GPU process) exits unexpectedly, allowing apps to respond with recovery logic or diagnostics.

Before this change: The CoreWebView2ProcessFailedEventArgs.Reason property returned Unexpected for three distinct exit scenarios (normal exit, abnormal exit, and code integrity failure), making it impossible for apps to distinguish between them.

After this change: When the msWebView2GranularProcessFailedReason feature flag is enabled, the CoreWebView2ProcessFailedEventArgs.Reason property returns the following new, granular CoreWebView2ProcessFailedReason enum values, instead of Unexpected:

  • NormalExit — The process exited normally (exit code 0).

  • AbnormalExit — The process exited abnormally (non-zero exit code), but did not crash or get killed.

  • IntegrityFailure — The OS terminated the process due to a code integrity failure, such as when a DLL fails Windows Code Integrity verification.

The msWebView2GranularProcessFailedReason feature flag is disabled by default in releases 148 and 149, giving apps two releases to proactively test. Starting in release 150, the feature will be enabled by default, and apps will receive the granular values. To validate your WebView2 app's behavior, enable the feature flag, as follows:

set WEBVIEW2_ADDITIONAL_BROWSER_ARGUMENTS=--enable-features=msWebView2GranularProcessFailedReason

This is a bug fix for the Runtime and SDK. These enum members are a modification of an existing stable API, and are available as part of this Prerelease SDK.

See also:

Experimental APIs (Phase 1: Experimental in Prerelease)

The following APIs are in Phase 1: Experimental in Prerelease, and have been added in this Prerelease SDK.

Origin Configuration API for WebView2

The Origin Configuration API enables WebView2 apps to apply different feature and security policies based on the origin of hosted content. By default, WebView2 enforces a uniform policy across all origins. This API allows apps to selectively enable or disable specific features (such as Enhanced Security Mode) for individual origins or origin patterns.

Use the SetOriginFeatures method on CoreWebView2Profile to configure feature settings for one or more origins. Origins can be specified as exact strings (such as https://contoso.com) or wildcard patterns (such as https://[*.]contoso.com) to match subdomains, protocols, or ports.

When multiple configurations apply to the same origin, the most specific pattern takes precedence, evaluated by hostname, then scheme, then port.

Use GetEffectiveFeaturesForOrigin to asynchronously retrieve the computed feature settings for a given origin.

Phase 2 (Stable in Prerelease)

The following enum members are a modification of an existing stable API, and are available as part of this Prerelease SDK.

Granular process failure reasons for the ProcessFailed event

Supplemented the CoreWebView2ProcessFailedReason.Unexpected enum member by adding more granular values, for the CoreWebView2ProcessFailedReason enum that's returned by the CoreWebView2ProcessFailedEventArgs.Reason property.

This is a breaking change; see Granular process failure reasons for the ProcessFailed event, above.

Bug fixes

  • Breaking change: Supplemented the CoreWebView2ProcessFailedReason.Unexpected enum member by adding more granular values, for the CoreWebView2ProcessFailedReason enum that's returned by the CoreWebView2ProcessFailedEventArgs.Reason property. See Granular process failure reasons for the ProcessFailed event, above.

  • Enabled histogram logging for browser process crashes in WebView2.

See also

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