VDB-344977 · CVE-2026-25905 · jfsa-2026-001653

mcp-run-python Pyodide API runPython/runPythonAsync improper isolation or compartmentalization

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.3	$0-$5k	0.00

Summaryinfo

A vulnerability has been found in mcp-run-python and classified as problematic. The affected element is the function runPython/runPythonAsync of the component Pyodide API. This manipulation causes improper isolation or compartmentalization. This vulnerability is tracked as CVE-2026-25905. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in mcp-run-python (the affected version unknown). It has been declared as problematic. Affected by this vulnerability is the function runPython/runPythonAsync of the component Pyodide API. The manipulation with an unknown input leads to a improper isolation or compartmentalization vulnerability. The CWE definition for the vulnerability is CWE-653. The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

The Python code being run by 'runPython' or 'runPythonAsync' is not isolated from the rest of the JS code, allowing any Python code to use the Pyodide APIs to modify the JS environment. This may result in an attacker hijacking the MCP server - for malicious purposes including MCP tool shadowing. Note - the "mcp-run-python" project is archived and unlikely to receive a fix.

The advisory is shared at research.jfrog.com. This vulnerability is known as CVE-2026-25905 since 02/08/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/09/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Programming Language Software

Name

mcp-run-python

CPE 2.3info

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CPE 2.2info

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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.0
VulDB Temp Score: 4.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.8
CNA Vector (JFROG): 🔒

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper isolation or compartmentalization
CWE: CWE-653
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

02/08/2026 CVE reserved
02/09/2026 +1 days Advisory disclosed
02/09/2026 +0 days VulDB entry created
02/09/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: jfsa-2026-001653
Status: Not defined

CVE: CVE-2026-25905 (🔒)
GCVE (CVE): GCVE-0-2026-25905
GCVE (VulDB): GCVE-100-344977

Entryinfo

Created: 02/09/2026 10:33
Changes: 02/09/2026 10:33 (62)
Complete: 🔍
Cache ID: 216::103