Junglewise Threat Intelligence

CVE-2026-35204: Helm path traversal in plugin metadata version field

CVE-2026-35204 · Severity: high · CVSS 8.6 · Published 2026-04-09

Technologies: Helm, helm.sh/helm/v4 (Go). Vendors: Helm, Go.

Executive brief

Helm is a popular package manager used to manage applications on Kubernetes. A security flaw allows a malicious plugin to write files to any location on a user's computer when the plugin is installed or updated. This could allow an attacker to overwrite critical system files or steal sensitive data, potentially leading to a full system compromise.

Technical details

A path traversal vulnerability (CWE-22) exists in Helm's plugin loading mechanism. The root cause is a failure to validate the 'version' field within a plugin's 'plugin.yaml' file, which can be manipulated to include POSIX dot-dot ('../') path separators. When a user installs or updates a specially crafted plugin, Helm uses this version string to construct a filesystem path, allowing the plugin's contents to be written outside the intended directory. This can lead to arbitrary file overwrite and potential code execution if system binaries or configuration files are replaced. The issue is fixed in version 4.1.4 by enforcing strict semantic versioning (SemVer) validation on the version field.

Affected products

  • Helm Helm >= 4.0.0, < 4.1.4

Timeline

  • 2026-04-09: advisory: Vendor advisory and GHSA published.
  • 2026-04-09: patched: Fixed in Helm version 4.1.4.

References

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