Helm v4.2.1 is a focused patch release addressing critical execution bugs. Key improvements include a fix for version range constraint logic, resolution of data races during concurrent operations, and corrected CLI output behavior where success messages were sent to stderr. The release also includes essential security updates for the internal networking stack and core Kubernetes dependencies.

Improved Version Range Constraint Handling — Prevents intermittent failures and 'unable to find exact version' errors when deploying charts with semantic version ranges. This ensures more reliable automated CD pipelines that rely on flexible version constraints.

Fixed Concurrency and Deletion Race Conditions — Resolves two distinct race conditions in the Kubernetes client, one affecting concurrent operations (like upgrade/rollback) and another causing early cancellations during resource deletion. This improves the stability of complex deployment scripts and CI/CD runs.

Security Patches and Dependency Updates — Addresses a known vulnerability (GO-2026-5026) in networking libraries and updates core Kubernetes dependencies. This ensures the tool used to manage your cluster remains secure and compatible with the latest Kubernetes components.