{"answers":{"affected":"2 open source packages ship an affected version, including mcp.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63118 exists.","fix":"Upgrade mcp to 0.23.0 or later.","what":"CVE-2026-63118 is a medium-severity server-side request forgery vulnerability in modelcontextprotocol ruby-sdk, published on 29 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-2026-63118 and fix it if it is affected.\n\nWhat it is: CVE-2026-63118 is a medium-severity server-side request forgery vulnerability in modelcontextprotocol ruby-sdk, published on 29 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63118 exists.\n\nAffected packages and fixed versions:\n- mcp (RubyGems): affected all versions; fixed in 0.23.0\n- mcp (RubyGems): affected all versions; fixed in 0.23.0\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-2026-63118/ (Markdown: https://insights.sbomify.com/CVE-2026-63118/index.md)","id":"CVE-2026-63118","markdown":"https://insights.sbomify.com/CVE-2026-63118/index.md","name":"CVE-2026-63118","record":{"aliases":["GHSA-rjr6-rcgv-9m7m"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Ruby MCP SDK","requires_auth":"none","summary":"Attackers can use DNS rebinding to access local MCP servers and invoke tools due to missing Host/Origin validation in the Ruby SDK.","user_interaction":"required","vuln_class":"ssrf"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":6.9,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-350","name":"Reliance on Reverse DNS Resolution for a Security-Critical Action"},{"id":"CWE-346","name":"Origin Validation Error"}],"description":"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.","ecosystems":["RubyGems"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection","id":"CVE-2026-63118","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"RubyGems","product":null,"products":[],"type":"ssrf","year":"2026"},"n_packages":2,"n_references":3,"next":{"headline":"MCP Ruby SDK: Unbounded line buffer in stdio transports leads to memory exhaustion (DoS)","id":"CVE-2026-63119"},"packages":[{"ecosystem":"RubyGems","fixed":["0.23.0"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":null,"source":"GHSA-rjr6-rcgv-9m7m"},{"ecosystem":"RubyGems","fixed":["0.23.0"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":"pkg:gem/mcp","source":"GHSA-rjr6-rcgv-9m7m"}],"prev":{"headline":"FreeRDP: Denial of service through ADPCM frame size calculation","id":"CVE-2026-63117"},"products":["ruby-sdk"],"published":"2026-07-29","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":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-29","vendors":["modelcontextprotocol"]},"summary":"Attackers can use DNS rebinding to access local MCP servers and invoke tools due to missing Host/Origin validation in the Ruby SDK.","url":"https://insights.sbomify.com/CVE-2026-63118/"}