GHSA-q5jf-9vfq-h4h7 Helm's plugin verification fails open when .prov is missing, allowing unsigned plugin install

• Go helm.sh/helm/v4: >= 4.0.0, < 4.1.4 → fixed in 4.1.4

Helm is a package manager for Charts for Kubernetes. In Helm versions >=4.0.0 and <=4.1.3, Helm will install plugins missing provenance (`.prov` file) when signature verification is required. Impact The bug allows plugin authors to omit provenance (signing) data from plugins, bypassing plugin signature verification upon plugin install/update. Notably, plugin hooks will be executed as designed on the installed plugin, enabling a malicious plugin to execute arbitrary code. Patches This issue has been patched in Helm v4.1.4 Installing/updating a plugin with missing provenance will error if signature verification is required. Workarounds Users may manually validate that a plugin archive is not missing provenance data (`.prov` file) before installation.