Mark3labs Mcp-go vulnerabilities
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Published CVEs affecting Mark3labs Mcp-go: 2 record(s), with affected versions and fixes.
CVE-2026-108859
High · 7.5
CWE-770 Oct 11, 2026
mcp-go through 1.2.1 Denial of Service via Unbounded POST Body Buffering
mcp-go through 1.2.1 contains a denial of service vulnerability in StreamableHTTPServer.ServeHTTP that allows remote unauthenticated attackers to exhaust memory by sending oversized POST bodies. Attackers can send arbitrarily large or many concurrent POST requests, read fully via io.ReadAll before validation, to degrade or OOM-kill the server process.
CVE-2026-81092
Medium · 6.8
CWE-346 Aug 27, 2026
mcp-go before 0.56.0 Missing Host Header Validation Enables DNS Rebinding
mcp-go accepted requests on its HTTP transports without checking the Host header. StreamableHTTPServer.ServeHTTP in server/streamable_http.go and SSEServer.ServeHTTP in server/sse.go served any request arriving over a loopback connection regardless of the host it named, and the SSE transport's cross-origin default allowed any origin. A page in a browser could therefore point a name it controlled at the loopback address and reach a server listening there, invoking tools and reading resources that the server exposed on the assumption that only local software could connect. No release before 0.56.0 validated the header on either transport; 0.56.0 adds server/http_localhost.go, which rejects a loopback-bound request carrying a host that is not a loopback name, and wires it into both transports.