CVE-2026-16496: CWE-384: Session Fixation in HashiCorp Tooling
The terraform-mcp-server before version 1.1.0 is vulnerable to an authorization bypass in the streamable-HTTP stateful transport mode that may allow a user who obtains another user's MCP session ID to have their tool calls executed using that user's Terraform credentials. This vulnerability, CVE-2026-16496, is fixed in terraform-mcp-server 1.1.0.
AI Analysis
Technical Summary
The terraform-mcp-server prior to version 1.1.0 suffers from a session fixation vulnerability (CWE-384) in its streamable-HTTP stateful transport mode. An attacker who acquires a valid MCP session ID belonging to another user can bypass authorization controls and perform actions using the victim's Terraform credentials. This vulnerability is identified as CVE-2026-16496 and has a CVSS 3.1 base score of 8.9, indicating high severity. The issue is resolved in terraform-mcp-server version 1.1.0.
Potential Impact
Successful exploitation allows an attacker to impersonate another user by reusing their MCP session ID, leading to unauthorized execution of Terraform tool calls with the victim's credentials. This compromises confidentiality and integrity of the victim's Terraform environment and may cause limited availability impact.
Mitigation Recommendations
Upgrade terraform-mcp-server to version 1.1.0 or later, where this session fixation vulnerability is fixed. Patch status is confirmed by the vendor advisory stating the fix is included in version 1.1.0. No other mitigation steps are indicated.
CVE-2026-16496: CWE-384: Session Fixation in HashiCorp Tooling
Description
The terraform-mcp-server before version 1.1.0 is vulnerable to an authorization bypass in the streamable-HTTP stateful transport mode that may allow a user who obtains another user's MCP session ID to have their tool calls executed using that user's Terraform credentials. This vulnerability, CVE-2026-16496, is fixed in terraform-mcp-server 1.1.0.
CVSS v3.1
Score 8.9high
Affected software
HashiCorp
Tooling
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The terraform-mcp-server prior to version 1.1.0 suffers from a session fixation vulnerability (CWE-384) in its streamable-HTTP stateful transport mode. An attacker who acquires a valid MCP session ID belonging to another user can bypass authorization controls and perform actions using the victim's Terraform credentials. This vulnerability is identified as CVE-2026-16496 and has a CVSS 3.1 base score of 8.9, indicating high severity. The issue is resolved in terraform-mcp-server version 1.1.0.
Potential Impact
Successful exploitation allows an attacker to impersonate another user by reusing their MCP session ID, leading to unauthorized execution of Terraform tool calls with the victim's credentials. This compromises confidentiality and integrity of the victim's Terraform environment and may cause limited availability impact.
Mitigation Recommendations
Upgrade terraform-mcp-server to version 1.1.0 or later, where this session fixation vulnerability is fixed. Patch status is confirmed by the vendor advisory stating the fix is included in version 1.1.0. No other mitigation steps are indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- HashiCorp
- Date Reserved
- 2026-07-21T16:53:07.388Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a68f3749c2644c7f803d819
Added to database: 07/28/2026, 18:22:44 UTC
Last enriched: 07/29/2026, 15:40:15 UTC
Last updated: 09/12/2026, 22:01:31 UTC
Views: 90
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