{"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-2026-63119 exists.","fix":"Upgrade mcp to 0.23.0 or later.","what":"CVE-2026-63119 is a medium-severity denial of service vulnerability in modelcontextprotocol ruby-sdk, published on 29 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-63119 and fix it if it is affected.\n\nWhat it is: CVE-2026-63119 is a medium-severity denial of service vulnerability in modelcontextprotocol ruby-sdk, published on 29 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63119 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-2026-63119/ (Markdown: https://insights.sbomify.com/CVE-2026-63119/index.md)","id":"CVE-2026-63119","markdown":"https://insights.sbomify.com/CVE-2026-63119/index.md","name":"CVE-2026-63119","record":{"aliases":["GHSA-7683-3w9x-ch42"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Ruby MCP SDK","requires_auth":"none","summary":"A malicious peer can exhaust process memory in the MCP Ruby SDK by sending data without newlines, causing a denial of service.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":6.2,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-770","name":"Allocation of Resources Without Limits or Throttling"},{"id":"CWE-400","name":"Uncontrolled Resource Consumption"}],"description":"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.","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: Unbounded line buffer in stdio transports leads to memory exhaustion (DoS)","id":"CVE-2026-63119","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"RubyGems","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":2,"n_references":3,"next":{"headline":"PGHoard: Incomplete Path Traversal fix in restore.py allows Arbitrary File Write","id":"CVE-2026-63120"},"packages":[{"ecosystem":"RubyGems","fixed":["0.23.0"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":null,"source":"GHSA-7683-3w9x-ch42"},{"ecosystem":"RubyGems","fixed":["0.23.0"],"introduced":["0"],"last_affected":[],"package":"mcp","purl":"pkg:gem/mcp","source":"GHSA-7683-3w9x-ch42"}],"prev":{"headline":"MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection","id":"CVE-2026-63118"},"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":"A malicious peer can exhaust process memory in the MCP Ruby SDK by sending data without newlines, causing a denial of service.","url":"https://insights.sbomify.com/CVE-2026-63119/"}