MCP Kotlin SDK is the Kotlin Multiplatform software development kit for the Model Context Protocol. In versions 0.7.0 through 0.12.0, "ReadBuffer.append" in "kotlin-sdk-core/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/ReadBuffer.kt" writes every chunk of bytes received from the stdio transport into a "kotlinx.io.Buffer" with no size cap. Frames are extracted from that buffer only when a "\n" (0x0a) byte is observed. A peer that streams bytes without ever sending a newline causes the internal buffer to grow indefinitely until the JVM (or the surrounding host process) is OOM-killed. The leak is amplified by "StdioServerTransport" and "StdioClientTransport", which both queue raw chunks through a "kotlinx.coroutines.channels.Channel<ByteArray>(Channel.UNLIMITED)" and then call "readBuffer.append(chunk)" without backpressure or size guard. This is a remote-pre-auth denial of service whenever an SDK stdio server's stdin is fed by an untrusted or attacker-controlled producer (for example: a host program that exec's the MCP server as a subprocess and pipes through bytes received from a network peer, or a sidecar wrapper that proxies bytes from an HTTP endpoint to the stdio transport). Version 0.13.0 fixes the issue.