CVE-2026-35205 — v4
Fix: helm/helm@05fa379CVE-2026-35205 is a CWE-636 vulnerability in helm.sh/helm/v4. A fix is available for helm.sh/helm/v4 — see the affected versions and patch details below.
Helm's plugin verification fails open when .prov is missing, allowing unsigned plugin install
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-35205.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
helm.sh/helm/v4Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | helm.sh/helm/v4 | ≥ 4.0.0&&< 4.1.4 | 4.1.4go get helm.sh/helm/v4@v4.1.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for helm.sh/helm/v4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update helm.sh/helm/v4 to 4.1.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35205 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-35205 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-35205. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Helm CLI 4.1 | helm-cli-4.1.4 | RHSA-2026:26441 |
Frequently Asked Questions
Is CVE-2026-35205 in your dependencies?
O3 Security finds CVE-2026-35205 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.