{"cve":"CVE-2026-52870","nvd":{"published":"2026-07-15T20:17:38.577","modified":"2026-10-24T21:10:00.130","status":"Analyzed","description":"The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). From 1.23.0 until 1.27.2, default handlers installed by server.experimental.enable_tasks() for tasks/list, tasks/get, tasks/result, and tasks/cancel operate only on task identifiers without recording the session that created each task, allowing any connected client to enumerate, read results from, consume messages for, or cancel other clients' tasks. This issue is fixed in version 1.27.2.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L","score":7.6},"cwes":["CWE-862"],"references":["https://github.com/modelcontextprotocol/python-sdk/commit/62137874ff26dd74d2fea80ff528a7fd9ca7a5e7","https://github.com/modelcontextprotocol/python-sdk/pull/2720","https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2","https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-hvrp-rf83-w775"],"products":["lfprojects:mcp_python_sdk"],"source":"nvd","synced_at":"2026-10-25T17:50:08.599881581+00:00"},"epss":{"cve":"CVE-2026-52870","score":0.00388,"percentile":0.32634,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-hvrp-rf83-w775","url":"https://osv.dev/vulnerability/GHSA-hvrp-rf83-w775","summary":"MCP Python SDK: Experimental task handlers allow any client to access and cancel other clients' tasks","modified":"2026-09-10T03:51:11.568526826Z","packages":[{"ecosystem":"PyPI","name":"mcp","purl":"pkg:pypi/mcp","ranges":[">=1.23.0 <1.27.2"],"fixed":["1.27.2"]}]},{"id":"PYSEC-2026-3481","url":"https://osv.dev/vulnerability/PYSEC-2026-3481","summary":"MCP Python SDK: Experimental task handlers allow any client to access and cancel other clients' tasks","modified":"2026-07-23T15:00:13.878977054Z","packages":[{"ecosystem":"PyPI","name":"mcp","purl":"pkg:pypi/mcp","ranges":[">=1.23.0 <1.27.2"],"fixed":["1.27.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}