CVE-2026-35206: Helm path traversal via Chart.yaml name dot-segment

CVE-2026-35206 · Severity: medium · CVSS 4.4 · Published 2026-04-09

Helm is a package manager used to manage applications on Kubernetes. A vulnerability in how it handles certain package names allows a malicious package to overwrite files in the user's current directory instead of extracting into a new folder. This could lead to the accidental loss or corruption of local configuration files or data when a user downloads and unpacks a specially crafted chart.

Technologies: helm.sh/helm/v3 (Go), helm.sh/helm/v4 (Go), Helm. Vendors: Go, Helm.

Quick answers

Is CVE-2026-35206 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-35206 being exploited in the wild.
How severe is CVE-2026-35206?
Medium severity, with a CVSS score of 4.4, published 9 April 2026.
Which products and versions are affected?
helm.sh/helm/v3 (Go) <= 3.20.1, SEMVER:introduced=0,fixed=3.20.2; helm.sh/helm/v4 (Go) <= 4.1.3, SEMVER:introduced=0,fixed=4.1.4; Helm <= 3.20.1, <= 4.1.3.
Is there a fix for CVE-2026-35206?
Yes. helm.sh/helm/v3 (Go): upgrade to 3.20.2 or later; helm.sh/helm/v4 (Go): upgrade to 4.1.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-35206 attacked?
It is attacked with local access, in a software library.
Am I affected by CVE-2026-35206?
Check whether you run helm.sh/helm/v3 (Go), helm.sh/helm/v4 (Go) or Helm at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • helm.sh/helm/v3 (Go): upgrade to 3.20.2 or later
    go get helm.sh/helm/v3@v3.20.2
  • helm.sh/helm/v4 (Go): upgrade to 4.1.4 or later
    go get helm.sh/helm/v4@v4.1.4

Technical details

A path traversal vulnerability (CWE-22) exists in Helm's chart extraction logic. When using 'helm pull --untar', a specially crafted Chart.yaml with a name field containing dot-segments ('.' or '..') can cause the extraction process to 'collapse' the directory structure. Instead of extracting to '<output dir>/<chart name>/', the contents are written directly into '<output dir>/'. While the implementation prevents traversal outside of the designated output directory, it fails to ensure a unique subdirectory is used, allowing an attacker to overwrite existing files within the target destination. This is fixed in Helm v3.20.2 and v4.1.4.

Affected products

  • Helm helm <= 3.20.1, <= 4.1.3

Identifiers

  • CVE-2026-35206
  • GHSA-hr2v-4r36-88hr
  • GO-2026-5435

Timeline

  • 2026-04-09: disclosed
  • 2026-04-09: patched
  • 2026-04-10: advisory

References

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