[Problem/Bug]: Can't connect to the remote debugging port in webview2 runtime 150.0.4078.65

[JasonChen-AT]

What happened?

I have webview2 app. I am using the following command to start the app which allows me to connect it over cdp in playwright.

set WEBVIEW2_ADDITIONAL_BROWSER_ARGUMENTS=--remote-debugging-port=9527
set WEBVIEW2_USER_DATA_FOLDER = C:\temp_9527
start "" "myapp.exe"

Then I use curl localhost:9527/json/version to verify it's able to connected to. Starting from webview2 runtime 150.0.4078.665, I can't get any info from /json/version. But 149.0.4022.98 is working fine.

Can someone help to take a look? Thanks.

The workaround is I use the fixed version for the webview2 runtime for myapp.

Importance

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

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

150.0.4078.665

SDK Version

No response

Framework

WPF

Operating System

Windows 11

OS Version

No response

Repro steps

see description

Repros in Edge Browser

No, issue does not reproduce in the corresponding Edge version

Regression

Regression in newer Runtime

Last working version (if regression)

No response

[anuragkumar878]

Hi @JasonChen-AT ,
In Runtime 150 security hardening for scenarios that involved an elevated (High-integrity) host process were added. WebView2 now ignores command-line switch overrides and HKCU policy values when read from an elevated process. From an elevated host, only HKLM policy and arguments the app passes directly via the API are honored while user entered ( WEBVIEW2_* environment variables and HKCU) are intentionally dropped.

Fix, please switch to a channel that survives elevation:
HKLM policy: HKLM\Software\Policies\Microsoft\Edge\WebView2\AdditionalBrowserArguments
OR Preferred in app change: CoreWebView2EnvironmentOptions.AdditionalBrowserArguments = "--remote-debugging-port=9222"

More on this in another thread here - #5640

[JasonChen-AT]

Thanks @anuragkumar878.