high7.6
CVE-2026-52870
The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP).
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | mcp | >= 1.23.0, <= 1.27.1 | 1.27.2 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Lfprojects | Mcp Python Sdk | from 1.23.0 before 1.27.2 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-hvrp-rf83-w775
- https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-hvrp-rf83-w775
- https://nvd.nist.gov/vuln/detail/CVE-2026-52870
- https://github.com/modelcontextprotocol/python-sdk/pull/2720
- https://github.com/modelcontextprotocol/python-sdk/commit/62137874ff26dd74d2fea80ff528a7fd9ca7a5e7
- https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2