# CVE-2026-16498: HashiCorp terraform-mcp-server cross-tenant credential reuse in stateless mode

Source: https://junglewise.ai/threats/cve-2026-16498-hashicorp-terraform-mcp-server-cross-tenant-credential-reuse-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-28. Updated: 2026-07-28  
License: CC BY 4.0 with a link back

CVE-2026-16498 · Severity: critical · CVSS 10 · Published 2026-07-28

HashiCorp terraform-mcp-server, a tool used to integrate Terraform with Model Context Protocol (MCP) clients, is vulnerable to a flaw that allows user credentials to be reused across different accounts. In specific configurations, the server fails to properly separate user sessions, meaning one user's authentication token could be used to perform actions on behalf of other users. This could lead to unauthorized access to sensitive infrastructure managed by Terraform, including the ability to view or modify cloud resources.

Technologies: [HashiCorp Terraform-Mcp-Server](https://junglewise.ai/threats/technologies/terraform-mcp-server). Vendors: [HashiCorp](https://junglewise.ai/threats/vendors/hashicorp).

## Quick answers

**Is CVE-2026-16498 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-16498 being exploited in the wild.

**How severe is CVE-2026-16498?** Critical severity, with a CVSS score of 10, published 28 July 2026.

**Which products and versions are affected?** HashiCorp terraform-mcp-server 0.2.1 up to and including 1.0.0.

**Is there a fix for CVE-2026-16498?** A patch was published on 2026-07-28. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-16498 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-16498?** Check whether you run HashiCorp Terraform-Mcp-Server. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A vulnerability exists in terraform-mcp-server when configured in stateless HTTP transport mode. The server's per-session Terraform client cache relies on session identifiers to isolate user credentials; however, in stateless mode, the underlying MCP library does not assign unique session identifiers. Consequently, the server fails to correctly isolate credentials across requests, causing the Terraform token supplied by one tenant to be reused for subsequent requests from other tenants. An unauthenticated remote attacker can exploit this to execute tool calls using the permissions of a previous user's token. This issue is fixed in version 1.1.0.

## Affected products

- HashiCorp terraform-mcp-server 0.2.1 up to and including 1.0.0

## Timeline

- 2026-07-28: disclosed
- 2026-07-28: patched

## References

- [https://discuss.hashicorp.com/t/hcsec-2026-23-multiple-vulnerabilities-impacting-hashicorp-terraform-mcp-server/77606](https://discuss.hashicorp.com/t/hcsec-2026-23-multiple-vulnerabilities-impacting-hashicorp-terraform-mcp-server/77606)

## Related threats

- [HashiCorp terraform-mcp-server auth bypass in stateful transport mode](https://junglewise.ai/threats/cve-2026-16496-hashicorp-terraform-mcp-server-auth-bypass-in-stateful-transport)
- [HashiCorp terraform-mcp-server SSRF in streamable-HTTP transport](https://junglewise.ai/threats/cve-2026-14869-hashicorp-terraform-mcp-server-ssrf-in-streamable-http-transport)