CVE-2026-109527 Model Context Protocol Python SDK - Denial of Service

Model Context Protocol Python SDK < 1.29.1 and 2.0.0a1 through 2.0.1 contain a denial of service caused by unbounded buffering of HTTP request bodies in Streamable HTTP session manager and related components, letting unauthenticated remote clients exhaust server memory, exploit requires network access to affected endpoints.

CVSS base score 7.5 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
View the NVD record ↗

Details

Type
Denial of Service
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
14 October 2026
Updated
15 October 2026
Weakness
CWE-770

Vendor fix

Upgrade to versions 1.29.1 or 2.1.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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