OAuth client could send credentials to an authorization server chosen by the MCP server

published 2026-09-28 last mo. modified 2026-10-23 22d ago

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository modelcontextprotocol/python-sdk. GitHub has not reviewed it into the GitHub Advisory Database and no CVE record has reached us yet, so everything here comes from the maintainers alone. Read the full advisory on GitHub.

cvss: 7.5; version 3.1, the maintainers
cisa kev: Not listed; not in CISA's catalog
epss: —; no score, EPSS covers CVEs only
public exploits: 0; none known

Security advisory published by the maintainers of modelcontextprotocol/python-sdk for mcp: the maintainers' own advisory, not a reviewed GitHub Advisory Database entry. The full advisory is on GitHub.

Patch / fix

fixed in 1

pypi mcp 1.30.0, 2.2.0

Is GHSA-qx49-fqc8-xw99 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CVSS scores

assigned by	version	score	vector
the maintainers	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
pypi	mcp	>=2.0.0a1, <2.2.0 >=1.9.1, <1.30.0	2.2.0 1.30.0

Classification

Weakness

CWE-345 Insufficient Verification of Data Authenticity
CWE-522 Insufficiently Protected Credentials

References

github.com /modelcontextprotocol/python-sdk/security/advisories/GHSA-qx49-fqc8-xw99
advisory

Sources

Maintainer advisory GHSA-qx49-fqc8-xw99

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of modelcontextprotocol/python-sdk published their own advisory on GitHub. Its facts and headline are shown here; the description stays on GitHub.