modelcontextprotocol python-sdk up to 1.9.3 uncaught exception

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.00

Summaryinfo

A vulnerability has been found in modelcontextprotocol python-sdk up to 1.9.3 and classified as problematic. Affected by this issue is some unknown functionality. The manipulation leads to uncaught exception. This vulnerability is referenced as CVE-2025-53366. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in modelcontextprotocol python-sdk up to 1.9.3. This issue affects an unknown part. The manipulation with an unknown input leads to a uncaught exception vulnerability. Using CWE to declare the problem leads to CWE-248. An exception is thrown from a function, but it is not caught. Impacted is availability. The summary by CVE is:

The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.9.4, a validation error in the MCP SDK can cause an unhandled exception when processing malformed requests, resulting in service unavailability (500 errors) until manually restarted. Impact may vary depending on the deployment conditions, and presence of infrastructure-level resilience measures. Version 1.9.4 contains a patch for the issue.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2025-53366 since 06/27/2025. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 1.9.4 eliminates this vulnerability. Applying the patch 29c69e6a47d0104d0afcea6ac35e7ab02fde809a is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-20093). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Uncaught exception
CWE: CWE-248
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: python-sdk 1.9.4
Patch: 29c69e6a47d0104d0afcea6ac35e7ab02fde809a

Timelineinfo

06/27/2025 CVE reserved
07/05/2025 +8 days Advisory disclosed
07/05/2025 +0 days VulDB entry created
07/05/2025 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-3qhf-m339-9g5v
Status: Confirmed

CVE: CVE-2025-53366 (🔒)
GCVE (CVE): GCVE-0-2025-53366
GCVE (VulDB): GCVE-100-314975
EUVD: 🔒

Entryinfo

Created: 07/05/2025 07:33
Updated: 07/05/2025 07:46
Changes: 07/05/2025 07:33 (35), 07/05/2025 07:34 (34), 07/05/2025 07:46 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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