CVE-2026-76286

Received Received - Intake

Splunk MCP Server Token Exposure Vulnerability

Publication date: 2026-10-07

Last updated on: 2026-10-07

Assigner: Cisco Systems, Inc.

Description

In Splunk MCP Server versions below 1.2.1, Splunk MCP Server could send the Splunk platform authentication token of a user who runs a custom Application Programming Interface (API) tool to the URL configured for that tool. If another user controls that URL, they could capture the token and use it to access data and perform actions as the user who ran the tool. Successful exploitation requires a user who holds a role that contains the mcp_tool_execute capability to run a custom API tool configured by another user. For more information see Configure the Splunk MCP Server (https://help.splunk.com/en/splunk-enterprise/mcp-server-for-splunk-platform/1.2/configure-the-splunk-mcp-server) and Managing custom tools in Splunk MCP Server (https://help.splunk.com/en/splunk-enterprise/mcp-server-for-splunk-platform/1.2/managing-custom-tools-in-splunk-mcp-server) in the Splunk documentation.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-07

Last Modified

2026-10-07

Generated

2026-10-08

AI Q&A

2026-10-08

EPSS Evaluated

N/A

NVD

CVE-2026-76286

Affected Vendors & Products

Vendor	Product	Version / Range
Splunk	Splunk	MCP Server 1.2

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-918	The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Attack-Flow Graph

Executive Summary

In Splunk MCP Server versions below 1.2.1, a vulnerability allows the server to send a user's Splunk platform authentication token to a URL configured for a custom API tool. If an attacker controls that URL, they can capture the token and use it to access data or perform actions as the affected user.

Impact Analysis

If you have a role with the mcp_tool_execute capability and run a custom API tool configured by another user, your authentication token could be exposed. An attacker could then impersonate you to access sensitive data or perform unauthorized actions in your Splunk environment.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, potentially violating compliance requirements such as GDPR or HIPAA. Exposure of authentication tokens may result in data breaches, triggering regulatory penalties or legal consequences.

Mitigation Strategies

Update Splunk MCP Server to version 1.2.1 or later to address the token exposure issue. Ensure users with the mcp_tool_execute capability are restricted to trusted roles only.

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