[Regression] WebView2 155.0.4283.45 renderer crashes with 0xC0000005; 154.0.4258.62 works #5758

Title: [Regression] WebView2 155.0.4283.45 renderer crashes with 0xC0000005; 154.0.4258.62 works

Description

WebView2 Evergreen Runtime 155.0.4283.45 consistently crashes its renderer on Windows 11 Home 25H2 (OS build 26200.9457).

The issue affects multiple unrelated applications, including Windows Search, WhatsApp Desktop and Google Drive for Desktop. It is also reproducible using Microsoft's official WebView2APISample application.

Switching the sample application to Fixed Version Runtime 154.0.4258.62 completely resolves the issue.

Reproduction

1. Install/use WebView2 Evergreen Runtime 155.0.4283.45.

2. Launch the official Microsoft WebView2APISample (x64, SDK build 902.0).

3. Observe the WebView2 child process failure.

4. Set WEBVIEW2_BROWSER_EXECUTABLE_FOLDER to an extracted Fixed Version Runtime 154.0.4258.62 x64.

5. Relaunch the same sample application. Web content renders correctly and remains responsive.

6. Remove the environment override and relaunch with Evergreen 155.0.4283.45. The renderer crashes again.

Actual result

The sample reports:

Kind: COREWEBVIEW2_PROCESS_FAILED_KIND_RENDER_PROCESS_EXITED
Reason: COREWEBVIEW2_PROCESS_FAILED_REASON_CRASHED
Exit code: -1073741819 (0xC0000005)

Google Drive displays a blank interface. WhatsApp Desktop incorrectly reports no internet connection. Windows Search displays a blank loading interface.

Expected result

The renderer starts successfully and applications display their web content normally.

Controlled test results

The version 154 tests used WEBVIEW2_BROWSER_EXECUTABLE_FOLDER, without replacing or modifying the installed Evergreen runtime.

Crash diagnostics

Three separate WhatsApp WebView2 Crashpad minidumps were inspected using WinDbg, including crashes from separate application launches.

All three show an identical failure signature:

Exception: 0xC0000005
Module: msedge.dll
Offset: 0xCAFBBE
Instruction: xor r9, qword ptr [r14+8]
r14: DBE7EF36B2C2EB76
Invalid read address: DBE7EF36B2C2EB7E

The failure is highly reproducible. The underlying cause of the invalid pointer has not been established.

Troubleshooting already performed

• Removed Avast antivirus and rebooted; issue persisted.

• Completed Windows 11 in-place repair installation preserving applications and files; issue persisted.

• System File Checker completed without integrity violations.

• Tested WebView2 with --disable-gpu and --no-sandbox; neither resolved the renderer crash.

• Verified that the issue reproduces independently in Microsoft's WebView2 sample.

Request

Please investigate a possible renderer regression or compatibility issue introduced between WebView2 154 and 155.

Crash dumps and additional diagnostics can be supplied through an appropriate private channel if required.

Importance

Blocking. My app's basic functions are not working due to this issue.

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

155.0.4283.45.

SDK Version

No response

Framework

Other

Operating System

Windows 11

OS Version

No response

Repro steps

Reproduction
Install/use WebView2 Evergreen Runtime 155.0.4283.45.

Launch the official Microsoft WebView2APISample (x64, SDK build 902.0).

Observe the WebView2 child process failure.

Set WEBVIEW2_BROWSER_EXECUTABLE_FOLDER to an extracted Fixed Version Runtime 154.0.4258.62 x64.

Relaunch the same sample application. Web content renders correctly and remains responsive.

Remove the environment override and relaunch with Evergreen 155.0.4283.45. The renderer crashes again.

Repros in Edge Browser

No, issue does not reproduce in the corresponding Edge version

Regression

Regression in newer Runtime

Last working version (if regression)

154.0.4258.62