{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-33946",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-03-24T19:50:52.105Z",
        "datePublished": "2026-03-27T21:20:07.900Z",
        "dateUpdated": "2026-03-30T18:42:43.387Z"
    },
    "containers": {
        "cna": {
            "title": "MCP Ruby SDK: Insufficient Session Binding Allows SSE Stream Hijacking via Session ID Replay",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-384",
                            "lang": "en",
                            "description": "CWE-384: Session Fixation",
                            "type": "CWE"
                        }
                    ]
                },
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-639",
                            "lang": "en",
                            "description": "CWE-639: Authorization Bypass Through User-Controlled Key",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "attackRequirements": "PRESENT",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "HIGH",
                        "vulnIntegrityImpact": "NONE",
                        "vulnAvailabilityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "subAvailabilityImpact": "NONE",
                        "baseScore": 8.2,
                        "baseSeverity": "HIGH",
                        "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
                        "version": "4.0"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-5cv7-wh35",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-5cv7-wh35"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/ruby-sdk/commit/db40143402d65b4fb6923cec42d2d72cb89b3874",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/ruby-sdk/commit/db40143402d65b4fb6923cec42d2d72cb89b3874"
                },
                {
                    "name": "https://hackerone.com/reports/3556146",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://hackerone.com/reports/3556146"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/csharp-sdk/blob/main/src/ModelContextProtocol.AspNetCore/SseHandler.cs#L93-L97",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/csharp-sdk/blob/main/src/ModelContextProtocol.AspNetCore/SseHandler.cs#L93-L97"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/go-sdk/blob/main/mcp/streamable.go#L281C1-L288C2",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/go-sdk/blob/main/mcp/streamable.go#L281C1-L288C2"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/python-sdk/blob/main/src/mcp/server/streamable_http.py#L680-L685",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/python-sdk/blob/main/src/mcp/server/streamable_http.py#L680-L685"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/streamable_http_server.rb",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/streamable_http_server.rb"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.9.2",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.9.2"
                }
            ],
            "affected": [
                {
                    "vendor": "modelcontextprotocol",
                    "product": "ruby-sdk",
                    "versions": [
                        {
                            "version": "< 0.9.2",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-03-27T21:20:07.900Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to version 0.9.2, the Ruby SDK's streamable_http_transport.rb implementation contains a session hijacking vulnerability. An attacker who obtains a valid session ID can completely hijack the victim's Server-Sent Events (SSE) stream and intercept all real-time data. Version 0.9.2 contains a patch."
                }
            ],
            "source": {
                "advisory": "GHSA-qvqr-5cv7-wh35",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "references": [
                    {
                        "url": "https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-5cv7-wh35",
                        "tags": [
                            "exploit"
                        ]
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-03-30T18:42:40.211983Z",
                                "id": "CVE-2026-33946",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "yes"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-03-30T18:42:43.387Z"
                }
            }
        ]
    }
}