Model Context Protocol Java SDK HTTP server transports allow memory exhaustion through unbounded request bodies
The Model Context Protocol Java SDK is the official Java SDK for Model Context Protocol servers and clients. From version 0.8.0 through 0.12.0 in the io.modelcontextprotocol.sdk:mcp artifact, from 0.13.0 through 0.18.3 and 1.0.0 through 1.1.3 in io.modelcontextprotocol.sdk:mcp-core, and from mcp-core 2.0.0-M1 through 2.0.0, the Servlet-based SSE, Streamable HTTP, and Stateless server transports read an HTTP request body into memory without enforcing a maximum size. An unauthenticated remote client able to reach an affected transport can stream an arbitrarily large POST body, including with chunked transfer encoding, until the Java process exhausts its heap and becomes unavailable. Authentication, Origin or Host validation, or an upstream request-size limit can reject the request before the vulnerable read. The maintained mcp-core lines are fixed in versions 0.18.4, 1.1.4, and 2.0.1.
CVE-2026-108395
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-108395
io.modelcontextprotocol.sdk:mcp
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
io.modelcontextprotocol.sdk:mcp-core
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "modelcontextprotocol",
"product": "io.modelcontextprotocol.sdk:mcp",
"versions": [
{
"status": "affected",
"version": ">= 0.8.0, < 0.13.0"
}
]
},
{
"vendor": "modelcontextprotocol",
"product": "io.modelcontextprotocol.sdk:mcp-core",
"versions": [
{
"status": "affected",
"version": ">= 0.13.0, < 0.18.4"
},
{
"status": "affected",
"version": ">= 1.0.0, < 1.1.4"
},
{
"status": "affected",
"version": ">= 2.0.0-M1, < 2.0.1"
}
]
}
]- Related CVEs
- CVE-2026-108395
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #23065 · Revision 1
- Added to Heist Feed
- Publisher date