CVE-2025-53365: MCP Python SDK Denial of Service via Streamable HTTP Transport
Attack on AI2 Disclosed vulnerabilityInfrastructure vulnerability
An unhandled exception in the Model Context Protocol Python SDK can cause server crashes during streamable HTTP sessions. Exploitation leads to a denial of service requiring manual service restarts.
disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why
Details
- type
- Attack on AIAn AI model, agent or AI-powered product was the thing exploited, abused or leaked.
- categories
- Infrastructure vulnerabilityCVEs and advisories in AI frameworks, inference servers, MCP servers, AI developer tools and hosting stacks.
- Infrastructure vulnerability
- owasp llm top 10
- mitre atlas
- no technique for these categoriesBoth rows are derived from the type and categories (OWASP 2025 edition, ATLAS release 2026.09), not classified per record. How
- severity
- 2 · Disclosed vulnerabilityCVE or vendor advisory, patched or patchable, no confirmed exploitation.
- targets
- Framework / tooling
- products
- mcp, mcp python sdk
- incident date
- 4 Jul 2025
- first reported
- 4 Jul 2025
- origin
- GitHub Advisory DatabaseVulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
- classifier confidence
- 0.95 · published at or above 0.80; see the methodology
- tags
- CVE-2025-53365 · mcp · dos
- record
- created 2026-10-18 07:00Z · updated 2026-10-18 10:04Z · json
Sources · 2
- 2025-07-04CVE-2025-53365: MCP Python SDK has Unhandled Exception in Streamable HTTP Transport, Leading to Denial of ServiceGitHub Advisory Database · github.com/advisories/GHSA-j975-95f5-7wqh
- 2025-07-04CVE-2025-53365: The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP).NVD · nvd.nist.gov/vuln/detail/CVE-2025-53365
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