---
id: CVE-2026-108714
title: >-
  MCP Kotlin SDK through 0.15.0 contains an uncontrolled memory allocation
  vulnerability that allows remote clients to exhaust server memory because
  Application.mcpWebSocket installs Ktor WebSockets without a maxFrameSize limit
summary: >-
  MCP Kotlin SDK through 0.15.0 contains an uncontrolled memory allocation
  vulnerability that allows remote clients to exhaust server memory because
  Application.mcpWebSocket installs Ktor WebSockets without a maxFrameSize
  limit. Attackers …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
published: '2026-10-11'
updated: '2026-10-11'
sourceUpdated: '2026-10-11T13:17:14.430'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-108714'
references:
  - url: 'https://github.com/modelcontextprotocol/kotlin-sdk'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/modelcontextprotocol/kotlin-sdk/blob/0.15.0/kotlin-sdk-core/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/WebSocketMcpTransport.kt#L60-L85
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/modelcontextprotocol/kotlin-sdk/blob/0.15.0/kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/WebSocketMcpKtorServerExtensions.kt#L41-L63
    label: disclosure@vulncheck.com
  - url: 'https://hackmd.io/@haind/mcp-kotlin-sdk-websocket-frame-allocation-dos'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/mcp-kotlin-sdk-through-0.15.0-memory-exhaustion-via-application-mcpwebsocket
    label: disclosure@vulncheck.com
tags:
  - nvd
ingestedAt: '2026-10-11T13:51:17.025Z'
---

## Overview

MCP Kotlin SDK through 0.15.0 contains an uncontrolled memory allocation vulnerability that allows remote clients to exhaust server memory because Application.mcpWebSocket installs Ktor WebSockets without a maxFrameSize limit. Attackers can send small frame headers declaring payloads near 2 GiB over one or a few connections, forcing huge heap allocations and causing denial of service.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.