{"id":"CVE-2025-53365","aliases":["GHSA-j975-95f5-7wqh","PYSEC-2026-1618"],"title":"MCP Python SDK has Unhandled Exception in Streamable HTTP Transport, Leading to Denial of Service","summary":"MCP Python SDK has Unhandled Exception in Streamable HTTP Transport, Leading to Denial of Service","severity":"high","vendor":"mcp","product":"mcp","ecosystem":"pip","affected":["mcp < 1.10.0"],"patched":["mcp 1.10.0"],"published":"2025-07-04","updated":"2026-07-07","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-j975-95f5-7wqh","references":[{"url":"https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-j975-95f5-7wqh"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-53365"},{"url":"https://github.com/modelcontextprotocol/python-sdk/pull/967"},{"url":"https://github.com/modelcontextprotocol/python-sdk/commit/7b420656de48cfdb90b39eb582e60b6d55c2f891"},{"url":"https://github.com/modelcontextprotocol/python-sdk"},{"url":"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.10.0"}],"tags":["osv","pip"],"epss":0.00367,"epssPercentile":0.30471,"ingestedAt":"2026-07-08T18:25:50.638Z","slug":"CVE-2025-53365","body":"## Overview\n\nIf a client deliberately triggers an exception after establishing a streamable HTTP session, this can lead to an uncaught ClosedResourceError on the server side, causing the server to crash and requiring a restart to restore service. Impact may vary depending on the deployment conditions, and presence of infrastructure-level resilience measures.\n\nThank you to Rich Harang for reporting this issue.\n\n## Affected packages\n\n- `mcp < 1.10.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `mcp 1.10.0`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}