{"answers":{"affected":"3 open source packages ship an affected version, including mcp. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-59950 in the wild and no public exploit code.","fix":"Upgrade mcp to 1.28.1 or later.","what":"CVE-2026-59950 is a high-severity missing authorization vulnerability in modelcontextprotocol python-sdk, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-59950 and fix it if it is affected.\n\nWhat it is: CVE-2026-59950 is a high-severity missing authorization vulnerability in modelcontextprotocol python-sdk, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2026-59950 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- mcp (PyPI): affected all versions; fixed in 1.28.1\n- mcp (PyPI): affected all versions; fixed in 1.28.1\n- mcp (PyPI): affected all versions; fixed in 1.28.1\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-59950/ (Markdown: https://insights.sbomify.com/CVE-2026-59950/index.md)","id":"CVE-2026-59950","markdown":"https://insights.sbomify.com/CVE-2026-59950/index.md","name":"CVE-2026-59950","record":{"aliases":["CLEANSTART-2026-FX89856","ECHO-754d-bf5b-8082","GHSA-vj7q-gjh5-988w","MINI-2q8x-779m-mhj2","MINI-45q8-xr38-hch6","MINI-4m66-qrgr-p4f8","MINI-6hp9-q5f8-cgr2","MINI-8265-xv5m-8gqv","MINI-9rh6-mf8q-8mw5","MINI-c4h8-pgvv-grhm","MINI-f665-xrmg-pp9w","MINI-p73h-3x4q-qccm","MINI-pj67-pvj7-62p4","MINI-qx7f-ghw8-7cj6","MINI-v7hm-6hfq-24gj","MINI-wjfw-rrv2-vcg2","MINI-x37v-9wqr-cqhq","MINI-x58c-vqqv-r7x7","MINI-xp5v-hp7v-fvc7","MINI-xqx5-q3rp-q72v","MINI-xrc5-5846-wqqm","PYSEC-2026-3483","ROOT-APP-PYPI-CVE-2026-59950"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"MCP Python SDK","requires_auth":"none","summary":"The MCP Python SDK WebSocket transport lacks Host/Origin validation, allowing unauthorized origins to connect to exposed applications.","user_interaction":"required","vuln_class":"missing_authorization"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"mcp_python_sdk","vendor":"lfprojects"}],"cvss":{"score":7.6,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-346","name":"Origin Validation Error"},{"id":"CWE-1385","name":"Missing Origin Validation in WebSockets"}],"description":"The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to 1.28.1, the deprecated mcp.server.websocket.websocket_server transport accepted WebSocket handshakes without applying Host or Origin header validation, leaving no SDK-level way to restrict which origins could connect to applications that exposed that transport. This issue is fixed in version 1.28.1.","ecosystems":["PyPI"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"MCP Python SDK: WebSocket server transport does not support Host/Origin validation","id":"CVE-2026-59950","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"missing_authorization","year":"2026"},"n_packages":3,"n_references":4,"next":{"headline":"MCP Python SDK: Unbounded Session Accumulation in StreamableHTTP Transport Enables Resource Exhaustion","id":"CVE-2026-59951"},"packages":[{"ecosystem":"PyPI","fixed":["1.28.1"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":null,"source":"GHSA-vj7q-gjh5-988w"},{"ecosystem":"PyPI","fixed":["1.28.1"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":"pkg:pypi/mcp","source":"GHSA-vj7q-gjh5-988w"},{"ecosystem":"PyPI","fixed":["1.28.1"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":"pkg:pypi/mcp","source":"PYSEC-2026-3483"}],"prev":{"headline":"LZ4 Java: Native XXHash implementations can crash the JVM when passed invalid byte array ranges","id":"CVE-2026-59949"},"products":["python-sdk"],"published":"2026-07-15","related":[{"cvss_score":7.6,"headline":"MCP Python SDK: Experimental task handlers allow any client to access and cancel other clients' tasks","id":"CVE-2026-52870","kev_date_added":null,"published":"2026-07-15"},{"cvss_score":7.6,"headline":"DNS Rebinding Protection Disabled by Default in Model Context Protocol Python SDK for Servers Running on Localhost","id":"CVE-2025-66416","kev_date_added":null,"published":"2025-12-02"},{"cvss_score":7.1,"headline":"MCP Python SDK: HTTP transports serve session requests without verifying the authenticated principal","id":"CVE-2026-52869","kev_date_added":null,"published":"2026-07-15"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-07-17","vendors":["modelcontextprotocol"]},"summary":"The MCP Python SDK WebSocket transport lacks Host/Origin validation, allowing unauthorized origins to connect to exposed applications.","url":"https://insights.sbomify.com/CVE-2026-59950/"}