CVE-2026-123139

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{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "modules": ["MCP Hub extension"], "platforms": ["Windows", "MacOS"], "product": "Neon", "vendor": "Opera", "versions": [{"status": "affected", "version": "1.0.0", "versionType": "custom"}]}], "source": "security@opera.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper verification of the source of a communication channel vulnerability in Opera Neon on macOS and Windows allows a malicious browser extension to take control of the browser by sending commands through MCP Hub to the built-in Browser Operator extension. This issue affects Opera Neon MCP Hub extension: 0.0.1."}], "id": "CVE-2026-123139", "lastModified": "2026-11-12T22:11:01.153", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "LOCAL", "availabilityRequirement": "NOT_DEFINED", "baseScore": 5.8, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "UNREPORTED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N/E:U/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security@opera.com", "type": "Secondary"}]}, "published": "2026-11-12T13:17:11.573", "references": [{"source": "security@opera.com", "url": "https://security.opera.com/en/improper-verification-of-source-of-a-communication-channel-opera-security-advisories/"}], "sourceIdentifier": "security@opera.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-940"}], "source": "security@opera.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": ["windows", "macos"], "status": "affected", "versions": {"scheme": "semver", "value": "1.0.0"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "original": {"product": "Neon", "source": "cna", "vendor": "Opera"}, "product": "neon", "vendor": "opera"}], "created": "2026-11-13T08:32:21.273889+00:00", "title": "Browser Control via Malicious Extension in Opera Neon MCP Hub", "updated": "2026-11-13T11:15:09.376961+00:00", "vendors": ["opera", "opera$PRODUCT$neon"]}