Threat
SVD-2026-1004 | Splunk Vulnerability Disclosure
Publication date unknown · Discovered splunk.com
Page published
Publication date unknown · First observed: 13 Oct 2026
Coverage timeline
Single-source advisory — one report is available.
Why it matters
CVE-2026-76286 shows how custom tool configuration in an MCP server can be weaponized to exfiltrate authentication tokens and hijack another user's privileges, a concrete risk for teams deploying agentic tool-calling infrastructure.
Splunk disclosed CVE-2026-76286 (SVD-2026-1004), a Server-Side Request Forgery flaw in Splunk MCP Server versions below 1.2.1. A user with the mcp_tool_admin capability can configure a custom API tool pointing to an attacker-controlled URL; when a user with the mcp_tool_execute capability runs that tool, the MCP server sends the executing user's Splunk platform authentication token to that URL, allowing the attacker to capture the token and act as that user. The fix is available in version 1.2.1.