Amazon.CDK.Lib 2.263.0: Amazon.CDK.Lib 2.263.0 hangs during App.Synth() with Node.js 24.x

Describe the bug

Environment Amazon.CDK.Lib: 2.263.0 Amazon.JSII.Runtime: 1.133.0 .NET SDK: 9.0.308 Node.js: 24.18.0 npm: 11.16.0 Windows 11

Observed behavior cdk ls hangs. cdk synth hangs. cdk deploy hangs. The application reaches app.Synth() and never returns. aws sts get-caller-identity works normally. Downgrading Amazon.CDK.Lib to 2.261.0 resolves the issue. Using Node 20 with Amazon.CDK.Lib 2.263.0 also resolves the issue.

Diagnostic information Simple stack trace:

Amazon.JSII.Runtime.Services.Runtime.ReadResponse()
Amazon.JSII.Runtime.Services.Client.ReceiveResponse()
Amazon.JSII.Runtime.Services.Client.Invoke()
Amazon.CDK.App.Synth()

A node.exe process grows to approximately 1.8 GB RAM while the .NET process blocks waiting for a JSII response.

Regression Issue

• Select this option if this issue appears to be a regression.

Last Known Working CDK Library Version

Amazon.CDK.Lib: 2.261.0

Expected Behavior

cdk deploy should work as before (with version 2.261.o)

Current Behavior

cdk deploy hanged

Reproduction Steps

See the stack trace above

Possible Solution

No response

Additional Information/Context

No response

AWS CDK Library version (aws-cdk-lib)

Amazon.CDK.Lib: 2.263.0

AWS CDK CLI version

2.1135.0 (build 0fa27ff)

Node.js Version

Node.js: 24.18.0

OS

Windows 11

Language

.NET

Language Version

.Net 8.0

Other information

No response