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    12 vulnerabilities found for ruby-sdk by modelcontextprotocol

    CVE-2026-67432 (GCVE-0-2026-67432)

    Vulnerability from nvd – Published: 2026-07-29 19:17 – Updated: 2026-07-29 19:34
    VLAI
    Title
    MCP Ruby SDK: Unbounded JSON-RPC request body causes uncontrolled memory allocation in StreamableHTTPTransport
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem reads and parses an entire JSON-RPC POST body without a size limit, allowing an unauthenticated remote attacker to exhaust process memory. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: none Automatable: yes Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-770 - Allocation of Resources Without Limits or Throttling
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-67431 (GCVE-0-2026-67431)

    Vulnerability from nvd – Published: 2026-07-29 19:15 – Updated: 2026-07-30 14:35
    VLAI
    Title
    MCP Ruby SDK: Ruby SSE Session Poisoning
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not bind a session ID to a session owner, allowing an attacker with a stolen session ID to send tools/call requests that execute in the victim's session. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: poc Automatable: yes Technical Impact: total
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-284 - Improper Access Control
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-67430 (GCVE-0-2026-67430)

    Vulnerability from nvd – Published: 2026-07-29 19:10 – Updated: 2026-07-30 15:19
    VLAI
    Title
    MCP Ruby SDK: Unbounded session retention in StreamableHTTPTransport allows memory exhaustion via initialize flood
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not expire sessions by default, so repeated initialize requests retain unbounded ServerSession objects and can exhaust process memory. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: poc Automatable: yes Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-401 - Missing Release of Memory after Effective Lifetime
    • CWE-770 - Allocation of Resources Without Limits or Throttling
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-63119 (GCVE-0-2026-63119)

    Vulnerability from nvd – Published: 2026-07-29 19:12 – Updated: 2026-07-29 19:28
    VLAI
    Title
    MCP Ruby SDK: Unbounded line buffer in stdio transports leads to memory exhaustion (DoS)
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StdioTransport and MCP::Client::Stdio in the mcp gem use IO#gets without a byte limit, allowing a peer that sends data without a newline to exhaust process memory. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: poc Automatable: no Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-400 - Uncontrolled Resource Consumption
    • CWE-770 - Allocation of Resources Without Limits or Throttling
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-63118 (GCVE-0-2026-63118)

    Vulnerability from nvd – Published: 2026-07-29 19:07 – Updated: 2026-07-29 19:35
    VLAI
    Title
    MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a locally running MCP server and invoke exposed tools. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: poc Automatable: no Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-346 - Origin Validation Error
    • CWE-350 - Reliance on Reverse DNS Resolution for a Security-Critical Action
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-33946 (GCVE-0-2026-33946)

    Vulnerability from nvd – Published: 2026-03-27 21:20 – Updated: 2026-03-30 18:42
    VLAI
    Title
    MCP Ruby SDK: Insufficient Session Binding Allows SSE Stream Hijacking via Session ID Replay
    Summary
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    SSVC
    Exploitation: poc Automatable: yes Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-384 - Session Fixation
    • CWE-639 - Authorization Bypass Through User-Controlled Key
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-67432 (GCVE-0-2026-67432)

    Vulnerability from cvelistv5 – Published: 2026-07-29 19:17 – Updated: 2026-07-29 19:34
    VLAI
    Title
    MCP Ruby SDK: Unbounded JSON-RPC request body causes uncontrolled memory allocation in StreamableHTTPTransport
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem reads and parses an entire JSON-RPC POST body without a size limit, allowing an unauthenticated remote attacker to exhaust process memory. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: none Automatable: yes Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-770 - Allocation of Resources Without Limits or Throttling
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-67431 (GCVE-0-2026-67431)

    Vulnerability from cvelistv5 – Published: 2026-07-29 19:15 – Updated: 2026-07-30 14:35
    VLAI
    Title
    MCP Ruby SDK: Ruby SSE Session Poisoning
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not bind a session ID to a session owner, allowing an attacker with a stolen session ID to send tools/call requests that execute in the victim's session. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: poc Automatable: yes Technical Impact: total
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-284 - Improper Access Control
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-63119 (GCVE-0-2026-63119)

    Vulnerability from cvelistv5 – Published: 2026-07-29 19:12 – Updated: 2026-07-29 19:28
    VLAI
    Title
    MCP Ruby SDK: Unbounded line buffer in stdio transports leads to memory exhaustion (DoS)
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StdioTransport and MCP::Client::Stdio in the mcp gem use IO#gets without a byte limit, allowing a peer that sends data without a newline to exhaust process memory. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: poc Automatable: no Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-400 - Uncontrolled Resource Consumption
    • CWE-770 - Allocation of Resources Without Limits or Throttling
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-67430 (GCVE-0-2026-67430)

    Vulnerability from cvelistv5 – Published: 2026-07-29 19:10 – Updated: 2026-07-30 15:19
    VLAI
    Title
    MCP Ruby SDK: Unbounded session retention in StreamableHTTPTransport allows memory exhaustion via initialize flood
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not expire sessions by default, so repeated initialize requests retain unbounded ServerSession objects and can exhaust process memory. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: poc Automatable: yes Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-401 - Missing Release of Memory after Effective Lifetime
    • CWE-770 - Allocation of Resources Without Limits or Throttling
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-63118 (GCVE-0-2026-63118)

    Vulnerability from cvelistv5 – Published: 2026-07-29 19:07 – Updated: 2026-07-29 19:35
    VLAI
    Title
    MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection
    Summary
    MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a locally running MCP server and invoke exposed tools. This issue is fixed in version 0.23.0.
    SSVC
    Exploitation: poc Automatable: no Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-346 - Origin Validation Error
    • CWE-350 - Reliance on Reverse DNS Resolution for a Security-Critical Action
    Assigner
    Impacted products
    Show details on NVD website

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    CVE-2026-33946 (GCVE-0-2026-33946)

    Vulnerability from cvelistv5 – Published: 2026-03-27 21:20 – Updated: 2026-03-30 18:42
    VLAI
    Title
    MCP Ruby SDK: Insufficient Session Binding Allows SSE Stream Hijacking via Session ID Replay
    Summary
    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.
    SSVC
    Exploitation: poc Automatable: yes Technical Impact: partial
    CISA Coordinator (v2.0.3)
    CWE
    • CWE-384 - Session Fixation
    • CWE-639 - Authorization Bypass Through User-Controlled Key
    Assigner
    Impacted products
    Show details on NVD website

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              "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"
            }
          ],
          "source": {
            "advisory": "GHSA-qvqr-5cv7-wh35",
            "discovery": "UNKNOWN"
          },
          "title": "MCP Ruby SDK: Insufficient Session Binding Allows SSE Stream Hijacking via Session ID Replay"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-33946",
        "datePublished": "2026-03-27T21:20:07.900Z",
        "dateReserved": "2026-03-24T19:50:52.105Z",
        "dateUpdated": "2026-03-30T18:42:43.387Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }