{"answers":{"affected":"4 open source packages ship an affected version, including mcp.","exploited":"There is no known exploitation of CVE-2026-116686 in the wild and no public exploit code.","fix":"Upgrade mcp to a fixed version for your release line: 1.30.0 or 2.2.0.","what":"CVE-2026-116686 is a medium-severity vulnerability in modelcontextprotocol python-sdk, published on 27 Oct 2026."},"fix_prompt":"Check this codebase for CVE-2026-116686 and fix it if it is affected.\n\nWhat it is: CVE-2026-116686 is a medium-severity vulnerability in modelcontextprotocol python-sdk, published on 27 Oct 2026. \nExploitation: There is no known exploitation of CVE-2026-116686 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- mcp (PyPI): affected from 1.10.0; fixed in 1.30.0\n- mcp (PyPI): affected from 1.10.0; fixed in 1.30.0\n- mcp (PyPI): affected from 2.0.0; fixed in 2.2.0\n- mcp (PyPI): affected from 2.0.0; fixed in 2.2.0\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-2026-116686/ (Markdown: https://insights.sbomify.com/CVE-2026-116686/index.md)","id":"CVE-2026-116686","markdown":"https://insights.sbomify.com/CVE-2026-116686/index.md","name":"CVE-2026-116686","record":{"aliases":["GHSA-rwrf-2pqf-9j8j"],"analysis":null,"analysis_generated_by":null,"assigner":"GitHub_M","cpe":[],"cvss":{"score":6.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-918","name":"Server-Side Request Forgery"}],"description":"The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.10.0 until 1.30.0 and 2.2.0, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema's default resolver, causing an unresolved $ref value to fetch an HTTP, HTTPS, or file URL from the client's network and filesystem context. A server can trigger blind requests or local-file reads and can stall every session in the process because resolution runs synchronously on the event loop without a timeout. This issue is fixed in versions 1.30.0 and 2.2.0.","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":"Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas","id":"CVE-2026-116686","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":null,"year":"2026"},"n_packages":4,"n_references":7,"next":{"headline":"CKEditor: Cross-site scripting (XSS) in the engine package","id":"CVE-2026-116687"},"packages":[{"ecosystem":"PyPI","fixed":["1.30.0"],"introduced":["1.10.0"],"last_affected":[],"package":"mcp","purl":null,"source":"GHSA-rwrf-2pqf-9j8j"},{"ecosystem":"PyPI","fixed":["1.30.0"],"introduced":["1.10.0"],"last_affected":[],"package":"mcp","purl":"pkg:pypi/mcp","source":"GHSA-rwrf-2pqf-9j8j"},{"ecosystem":"PyPI","fixed":["2.2.0"],"introduced":["2.0.0"],"last_affected":[],"package":"mcp","purl":null,"source":"GHSA-rwrf-2pqf-9j8j"},{"ecosystem":"PyPI","fixed":["2.2.0"],"introduced":["2.0.0"],"last_affected":[],"package":"mcp","purl":"pkg:pypi/mcp","source":"GHSA-rwrf-2pqf-9j8j"}],"prev":{"headline":"Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies","id":"CVE-2026-116685"},"products":["python-sdk"],"published":"2026-10-27","related":[],"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":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-28","vendors":["modelcontextprotocol"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-116686/"}