Is CVE-2026-108395 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-108395 being exploited in the wild.

How severe is CVE-2026-108395?

High severity, with a CVSS score of 7.5, published 14 October 2026.

Which products and versions are affected?

Model Context Protocol Java SDK mcp 0.8.0 through 0.12.0, mcp-core 0.13.0 through 0.18.3, mcp-core 1.0.0 through 1.1.3, mcp-core 2.0.0-M1 through 2.0.0.

How is CVE-2026-108395 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-108395?

Check whether you run Model Context Protocol Java SDK at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-108395: Model Context Protocol Java SDK unbounded HTTP request body read

CVE-2026-108395 · Severity: high · CVSS 7.5 · Published 2026-10-14

The Model Context Protocol Java SDK provides official support for building MCP servers and clients in Java applications. The Servlet-based SSE, Streamable HTTP, and Stateless server transports fail to limit incoming HTTP request body sizes, allowing unauthenticated attackers to stream arbitrarily large POST payloads—including chunked requests—until the Java process runs out of memory and crashes, causing service outages.

Vendors: Model Context Protocol.

Quick answers

Is CVE-2026-108395 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-108395 being exploited in the wild.
How severe is CVE-2026-108395?: High severity, with a CVSS score of 7.5, published 14 October 2026.
Which products and versions are affected?: Model Context Protocol Java SDK mcp 0.8.0 through 0.12.0, mcp-core 0.13.0 through 0.18.3, mcp-core 1.0.0 through 1.1.3, mcp-core 2.0.0-M1 through 2.0.0.
Is there a fix for CVE-2026-108395?: Yes: fixed in mcp-core 0.18.4, 1.1.4, 2.0.1. Until then: Apply authentication, Host or Origin validation, or enforce an upstream request-size limit to reject oversized requests before they reach the vulnerable transports. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-108395 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-108395?: Check whether you run Model Context Protocol Java SDK at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: mcp-core 0.18.4, 1.1.4, 2.0.1

Apply authentication, Host or Origin validation, or enforce an upstream request-size limit to reject oversized requests before they reach the vulnerable transports.

Technical details

The vulnerable Servlet-based HTTP server transports (SSE, Streamable HTTP, and Stateless) read request bodies into memory without enforcing a maximum size limit, allowing an unauthenticated remote attacker to exhaust heap memory via large or chunked POST requests. The vulnerability is mitigated only if authentication, Host/Origin validation, or an upstream request-size limit is in place. Fixed in mcp-core versions 0.18.4, 1.1.4, and 2.0.1.

Affected products

Model Context Protocol Java SDK mcp 0.8.0 through 0.12.0, mcp-core 0.13.0 through 0.18.3, mcp-core 1.0.0 through 1.1.3, mcp-core 2.0.0-M1 through 2.0.0

Timeline

2026-10-14: disclosed

References

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