Is CVE-2025-53365 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2025-53365 being exploited in the wild.

How severe is CVE-2025-53365?

High severity, with a CVSS score of 4, published 4 July 2025.

Which products and versions are affected?

Anthropic Model Context Protocol < 1.10.0; mcp (PyPI) ECOSYSTEM:introduced=0,fixed=1.10.0.

Is there a fix for CVE-2025-53365?

Yes. mcp (PyPI): upgrade to 1.10.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2025-53365 attacked?

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

Am I affected by CVE-2025-53365?

Check whether you run Anthropic Model Context Protocol or mcp (PyPI) 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-2025-53365: Model Context Protocol Python SDK denial of service in HTTP transport

Q: Is there a fix for CVE-2025-53365?

Yes. mcp (PyPI): upgrade to 1.10.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2025-53365 attacked?

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

Q: Am I affected by CVE-2025-53365?

Check whether you run Anthropic Model Context Protocol or mcp (PyPI) 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-2025-53365 · Severity: high · CVSS 4 · Published 2025-07-04

The Model Context Protocol (MCP) Python SDK contains a flaw that allows a remote user to crash the server. By establishing a specific type of web connection and then triggering an error, an attacker can force the server to shut down unexpectedly. This results in a denial of service, requiring a manual restart to restore operations.

Technologies: Anthropic Model Context Protocol, mcp (PyPI). Vendors: Anthropic, PyPI.

Quick answers

Is CVE-2025-53365 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2025-53365 being exploited in the wild.
How severe is CVE-2025-53365?: High severity, with a CVSS score of 4, published 4 July 2025.
Which products and versions are affected?: Anthropic Model Context Protocol < 1.10.0; mcp (PyPI) ECOSYSTEM:introduced=0,fixed=1.10.0.
Is there a fix for CVE-2025-53365?: Yes. mcp (PyPI): upgrade to 1.10.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2025-53365 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2025-53365?: Check whether you run Anthropic Model Context Protocol or mcp (PyPI) 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

mcp (PyPI): upgrade to 1.10.0 or later
```
pip install "mcp>=1.10.0"
```

Technical details

An unhandled exception vulnerability (CWE-248) exists in the MCP Python SDK's streamable HTTP transport component. If a client establishes a streamable HTTP session and subsequently triggers an exception, the server fails to catch a 'ClosedResourceError'. This uncaught exception leads to a process crash. The attack can be carried out over the network without prior authentication or user interaction. A fix is available in version 1.10.0, which implements proper exception handling for these transport sessions.

Affected products

Model Context Protocol mcp < 1.10.0

Identifiers

CVE-2025-53365
GHSA-j975-95f5-7wqh
PYSEC-2026-1618

Timeline

2025-07-04: disclosed
2025-07-04: advisory
2025-07-04: patched: Version 1.10.0 released

References

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