CVE-2026-76286

Server-Side Request Forgery (SSRF) through Custom API Tools in Splunk MCP Server

Severity
Medium 5.3
CVSS 3.1
Remote, needs privileges or user interaction what this means
Exploited
Not listed
EPSS
—
Discovered by
Not disclosed
Published
Oct 7, 2026
Assigned by cisco

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.

Weakness: CWE-918

Affected products

Vendor Product Category Matched by
Cisco Splunk Apps & Add-ons SIEM & Log Management cna-assigner
Vendor-reported products (1)
  • Splunk · Splunk MCP Server

Credit

Kuniyoshi Noguchi (KuniNogu)

Vendor remediation

Upgrade Splunk MCP Server to version 1.2.1 or higher.

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