Critical 10.0 CVSS Flaw in Terraform MCP Server: Cross-Tenant Credential Reuse Exploit Exposed
Overview
A zero-day vulnerability in Terraform MCP Server (CVE-2026-16498) enables cross-tenant credential theft in shared deployments, exposing enterprise cloud configurations to lateral movement attacks. Immediate patching is required to prevent token-based privilege escalation across multi-tenant environments.
Technical Analysis
The vulnerability stems from improper session isolation in stateless streamable-HTTP mode, where Terraform API tokens persist across user sessions. Attackers can connect sequentially to a shared MCP endpoint to harvest and reuse cached credentials. This permits unauthorized tool execution, workspace enumeration, and state file exfiltration with the privileges of prior users, leveraging timing attacks in concurrent session handling.
Enterprise & DIB Impact
For DIB contractors and enterprises using Terraform Cloud/Enterprise, this flaw risks exposure of IP-bonded infrastructure manifests, classified data storage configurations, and compliance-critical secrets. Shared MCP deployments in cloud engineering teams become vectors for cross-tenant data exfiltration and supply chain compromise, particularly in government-contracted environments.
Recommended Actions
- Upgrade to terraform-mcp-server 1.1.0 immediately
- verify multi-tenant deployment usage patterns
- implement session-timeout hardening
- monitor Terraform API access logs for anomalous tool-caller IP patterns
- and validate IAM policies restrict MCP endpoints to whitelisted engineering workstations only.
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