# Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies

Advisory record · `GHSA-5h93-6whr-6q8j`

- **Identifiers:** `GHSA-5h93-6whr-6q8j` · `CVE-2026-116685`
- **State:** Confirmed
- **Severity:** CVSS 5.9 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-200](https://cwe.mitre.org/data/definitions/200.html)
- **Tags:** [Information disclosure](https://agentprime.io/advisories/tag/info-disclosure.md)
- **Published:** 27 Oct 2026
- **Updated:** 27 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 27 Oct 2026, 21:05 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `mcp` (PyPI): affected `>=2.0.0, <2.2.0 || >=1.8.0, <1.30.0`; fixed in `2.2.0`, `1.30.0`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.9 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0040, the 34th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:07 UTC: First seen by agentprime
- 31 Oct 2026, 14:07 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-5h93-6whr-6q8j)

## Sources

- [GitHub Advisory Database: GHSA-5h93-6whr-6q8j](https://github.com/advisories/GHSA-5h93-6whr-6q8j)
- [OSV: GHSA-5h93-6whr-6q8j](https://osv.dev/vulnerability/GHSA-5h93-6whr-6q8j)
- <https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-5h93-6whr-6q8j>
- <https://github.com/modelcontextprotocol/python-sdk/pull/3397>
- <https://github.com/modelcontextprotocol/python-sdk/pull/3448>
- <https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c73fef2c12903d00aa6e>
- <https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b617db216d00fbd1d0bf99>
- <https://github.com/modelcontextprotocol/python-sdk>
- <https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0>
- <https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-5h93-6whr-6q8j>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-5h93-6whr-6q8j/>. Everything for agents: <https://agentprime.io/llms.txt>.