{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-45019",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-05-08T16:58:28.895Z",
        "datePublished": "2026-08-25T19:20:59.339Z",
        "dateUpdated": "2026-08-25T19:20:59.339Z"
    },
    "containers": {
        "cna": {
            "title": "Chainlit: SSRF via MCP SSE and streamable-http transports allows unauthenticated internal network access",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-918",
                            "lang": "en",
                            "description": "CWE-918: Server-Side Request Forgery (SSRF)",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "NONE",
                        "baseScore": 7.2,
                        "baseSeverity": "HIGH",
                        "confidentialityImpact": "LOW",
                        "integrityImpact": "LOW",
                        "privilegesRequired": "NONE",
                        "scope": "CHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/Chainlit/chainlit/security/advisories/GHSA-hvfh-5mj3-5f3j",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/Chainlit/chainlit/security/advisories/GHSA-hvfh-5mj3-5f3j"
                },
                {
                    "name": "https://github.com/Chainlit/chainlit/commit/0565fd0eccb915fce159929598b053ed79f6e0c9",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/Chainlit/chainlit/commit/0565fd0eccb915fce159929598b053ed79f6e0c9"
                },
                {
                    "name": "https://github.com/Chainlit/chainlit/blob/2.12.0/docs/security-advisory-2026-mcp.md#spl-2026-002--ssrf-via-mcp-streamable-http--sse",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/Chainlit/chainlit/blob/2.12.0/docs/security-advisory-2026-mcp.md#spl-2026-002--ssrf-via-mcp-streamable-http--sse"
                },
                {
                    "name": "https://github.com/Chainlit/chainlit/releases/tag/2.12.0",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/Chainlit/chainlit/releases/tag/2.12.0"
                }
            ],
            "affected": [
                {
                    "vendor": "Chainlit",
                    "product": "chainlit",
                    "versions": [
                        {
                            "version": ">= 2.4.0rc0, < 2.12.0",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-08-25T19:20:59.339Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Chainlit is a Python framework for building production-ready conversational AI applications. From 2.4.0rc0 until 2.12.0, Chainlit deployments with features.mcp.enabled set to true in .chainlit/config.toml expose the POST /mcp endpoint without requiring authentication. For sse and streamable-http transports, ConnectSseMCPRequest and ConnectStreamableHttpMCPRequest in backend/chainlit/types.py accept a user-controlled url and optional headers dictionary without scheme validation, private-address filtering, or an allowlist. The connect_mcp handler in backend/chainlit/server.py passes these values to sse_client() or streamablehttp_client(), allowing the Chainlit server to make blind outbound requests to arbitrary internal or external services, including cloud metadata endpoints, with attacker-controlled Authorization and Cookie headers. The SSE URL sink has existed since 2.4.0rc0, while attacker-controlled header forwarding and streamable-http support were added in 2.6.4. The response is consumed internally and not returned, but the attacker can issue state-changing authenticated requests, discover internal services, scan ports, and probe metadata endpoints. This issue is fixed in version 2.12.0."
                }
            ],
            "source": {
                "advisory": "GHSA-hvfh-5mj3-5f3j",
                "discovery": "UNKNOWN"
            }
        }
    }
}