Describe the bug

For our tests on macos-26 we set MallocStackLogging=1 to catch any stack allocation errors. When moving to macos-26, I started seeing it when calling the AWS CLI.

I created a simple workflow that shows the problem.

https://github.com/jeffadair/aws_macos_error/actions/runs/26888603504/job/79307836582#step:3:38

Regression Issue

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

Expected Behavior

Fix the memory error so it is no longer flagged by the system.

Current Behavior

After setting the MallocStackLogging=1 env var, running aws --version will cause and error thrown by the system.

Reproduction Steps

After setting the MallocStackLogging=1 env var, running aws --version will cause and error thrown by the system.

This workflow will reproduce it: https://github.com/jeffadair/aws_macos_error/blob/main/.github/workflows/repro.yml

Possible Solution

No response

Additional Information/Context

No response

CLI version used

aws-cli/2.34.53 Python/3.14.5 Darwin/25.4.0 exe/arm64

Environment details (OS name and version, etc.)

macos-26 runner