Is CVE-2026-116685 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-116685?

CVE-2026-116685 has a CVSS v3 severity of MEDIUM (5.9).

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CVE-2026-116685

Description

The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.8.0 until 1.30.0 and 2.2.0, streamable_http_client, streamablehttp_client, sse_client, ClientSessionGroup, OAuth, and create_mcp_http_client client paths enable follow_redirects and follow redirects to a different origin, forwarding caller-supplied custom credential headers and, for 307 or 308 responses, the request body. An attacker who can influence a trusted endpoint's redirect destination can receive that material. This issue is fixed in versions 1.30.0 and 2.2.0.