{"answers":{"affected":"3 open source packages ship an affected version, including mcp. It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-66416 in the wild and no public exploit code.","fix":"Upgrade mcp to 1.23.0 or later.","what":"CVE-2025-66416 is a high-severity server-side request forgery vulnerability in modelcontextprotocol python-sdk, published on 2 Dec 2025. 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-2025-66416 and fix it if it is affected.\n\nWhat it is: CVE-2025-66416 is a high-severity server-side request forgery vulnerability in modelcontextprotocol python-sdk, published on 2 Dec 2025. 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-2025-66416 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- mcp (PyPI): affected all versions; fixed in 1.23.0\n- mcp (PyPI): affected all versions; fixed in 1.23.0\n- mcp (PyPI): affected all versions; fixed in 1.23.0\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-2025-66416/ (Markdown: https://insights.sbomify.com/CVE-2025-66416/index.md)","id":"CVE-2025-66416","markdown":"https://insights.sbomify.com/CVE-2025-66416/index.md","name":"CVE-2025-66416","record":{"aliases":["GHSA-9h52-p55h-vw2f","PYSEC-2026-1617","ROOT-APP-PYPI-CVE-2025-66416"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass","code_execution"],"network_reachable":"yes","non_default_config":true,"product_category":"MCP Python SDK","requires_auth":"none","summary":"Attackers can use DNS rebinding to access local MCP servers if authentication is disabled, allowing unauthorized tool invocation.","user_interaction":"required","vuln_class":"ssrf"},"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-1188","name":"Initialization of a Resource with an Insecure Default"}],"description":"The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.23.0, tThe Model Context Protocol (MCP) Python SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication using FastMCP with streamable HTTP or SSE transport, and has not configured TransportSecuritySettings, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. Note that running HTTP-based MCP servers locally without authentication is not recommended per MCP security best practices. This issue does not affect servers using stdio transport. This vulnerability is fixed in 1.23.0.","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":"DNS Rebinding Protection Disabled by Default in Model Context Protocol Python SDK for Servers Running on Localhost","id":"CVE-2025-66416","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"ssrf","year":"2025"},"n_packages":3,"n_references":2,"next":{"headline":"GLPI has an unauthenticated SQL injection through the inventory endpoint","id":"CVE-2025-66417"},"packages":[{"ecosystem":"PyPI","fixed":["1.23.0"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":null,"source":"GHSA-9h52-p55h-vw2f"},{"ecosystem":"PyPI","fixed":["1.23.0"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":"pkg:pypi/mcp","source":"GHSA-9h52-p55h-vw2f"},{"ecosystem":"PyPI","fixed":["1.23.0"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":"pkg:pypi/mcp","source":"PYSEC-2026-1617"}],"prev":{"headline":"fastify-reply-from bypass of reply forwarding","id":"CVE-2025-66415"},"products":["python-sdk"],"published":"2025-12-02","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":"MCP Python SDK: WebSocket server transport does not support Host/Origin validation","id":"CVE-2026-59950","kev_date_added":null,"published":"2026-07-15"},{"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":"2025-12-02","vendors":["modelcontextprotocol"]},"summary":"Attackers can use DNS rebinding to access local MCP servers if authentication is disabled, allowing unauthorized tool invocation.","url":"https://insights.sbomify.com/CVE-2025-66416/"}