modelcontextprotocol php-sdk vulnerabilities

Latest modelcontextprotocol php-sdk CVEs

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1. CVE-2026-53965 MCP PHP SDK: Unbounded SSE buffer in HttpTransport enables client-side denial of service

   Published 2026-08-25

   Medium·CVSS 6.9 EPSS 0.62% PoC

   The MCP PHP SDK (Composer package mcp/sdk) is the official Model Context Protocol SDK for PHP. In versions 0.5.0 through 0.7.0, the HTTP client transport reads a Server-Sent Events response stream incrementally and appends each chunk to an in-memory buffer with no upper bound. Th...

Sources: CVE.org, NVD, CISA KEV, FIRST EPSS, OSV and public exploit-reference metadata. Product matching comes from the published CVE records. A proof-of-concept means public code exists; it is not evidence of exploitation.