GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2026-16496 (GCVE-0-2026-16496)

Vulnerability from cvelistv5 – Published: 2026-07-28 17:57 – Updated: 2026-07-28 18:43
VLAI
Title
terraform-mcp-server vulnerable to cross-user credential inheritance if an MCP session ID is obtained by another user
Summary
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.
Severity
8.9 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-28 18:42 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
HashiCorp Tooling Affected: 0.3.0 , < 1.1.0 (semver)
guessed Create a notification for this product.
Credits
This issue was reported to HashiCorp by Juan Pablo Martinez Kuhn of Coinspect.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-16496",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-28T18:42:15.101188Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-28T18:43:58.385Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "platforms": [
            "64 bit",
            "32 bit",
            "x86",
            "ARM",
            "MacOS",
            "Windows",
            "Linux"
          ],
          "product": "Tooling",
          "repo": "https://github.com/hashicorp/terraform-mcp-server",
          "vendor": "HashiCorp",
          "versions": [
            {
              "lessThan": "1.1.0",
              "status": "affected",
              "version": "0.3.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "This issue was reported to HashiCorp by Juan Pablo Martinez Kuhn of Coinspect."
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eThe 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\u0027s MCP session ID to have their tool calls executed using that user\u0027s Terraform credentials. This vulnerability, CVE-2026-16496, is fixed in terraform-mcp-server 1.1.0.\u003c/p\u003e\u003cbr/\u003e"
            }
          ],
          "value": "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\u0027s MCP session ID to have their tool calls executed using that user\u0027s Terraform credentials. This vulnerability, CVE-2026-16496, is fixed in terraform-mcp-server 1.1.0."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-60",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-60: Reusing Session IDs (Session Replay)"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.9,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-384",
              "description": "CWE-384: Session Fixation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-28T17:57:36.795Z",
        "orgId": "67fedba0-ff2e-4543-ba5b-aa93e87718cc",
        "shortName": "HashiCorp"
      },
      "references": [
        {
          "url": "https://discuss.hashicorp.com/t/hcsec-2026-23-multiple-vulnerabilities-impacting-hashicorp-terraform-mcp-server/77606"
        }
      ],
      "source": {
        "advisory": "HCSEC-2026-23",
        "discovery": "EXTERNAL"
      },
      "title": "terraform-mcp-server vulnerable to cross-user credential inheritance if an MCP session ID is obtained by another user"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "67fedba0-ff2e-4543-ba5b-aa93e87718cc",
    "assignerShortName": "HashiCorp",
    "cveId": "CVE-2026-16496",
    "datePublished": "2026-07-28T17:57:36.795Z",
    "dateReserved": "2026-07-21T16:53:07.388Z",
    "dateUpdated": "2026-07-28T18:43:58.385Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-16496",
      "date": "2026-09-20",
      "epss": "0.00369",
      "percentile": "0.30734"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "platforms": [
                  "64 bit",
                  "32 bit",
                  "x86",
                  "ARM",
                  "MacOS",
                  "Windows",
                  "Linux"
                ],
                "product": "Tooling",
                "repo": "https://github.com/hashicorp/terraform-mcp-server",
                "vendor": "HashiCorp",
                "versions": [
                  {
                    "lessThan": "1.1.0",
                    "status": "affected",
                    "version": "0.3.0",
                    "versionType": "semver"
                  }
                ]
              }
            ],
            "source": "security@hashicorp.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "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\u0027s MCP session ID to have their tool calls executed using that user\u0027s Terraform credentials. This vulnerability, CVE-2026-16496, is fixed in terraform-mcp-server 1.1.0."
          }
        ],
        "id": "CVE-2026-16496",
        "lastModified": "2026-07-30T14:08:23.057",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "LOW",
                "baseScore": 8.9,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L",
                "version": "3.1"
              },
              "exploitabilityScore": 2.2,
              "impactScore": 6.0,
              "source": "security@hashicorp.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-16496",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-28T18:42:15.101188Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-07-28T19:17:31.983",
        "references": [
          {
            "source": "security@hashicorp.com",
            "url": "https://discuss.hashicorp.com/t/hcsec-2026-23-multiple-vulnerabilities-impacting-hashicorp-terraform-mcp-server/77606"
          }
        ],
        "sourceIdentifier": "security@hashicorp.com",
        "vulnStatus": "Deferred",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-384"
              }
            ],
            "source": "security@hashicorp.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-16496",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-07-28T18:42:15.101188Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-07-28T18:42:50.919Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "platforms": [
                "64 bit",
                "32 bit",
                "x86",
                "ARM",
                "MacOS",
                "Windows",
                "Linux"
              ],
              "product": "Tooling",
              "repo": "https://github.com/hashicorp/terraform-mcp-server",
              "vendor": "HashiCorp",
              "versions": [
                {
                  "lessThan": "1.1.0",
                  "status": "affected",
                  "version": "0.3.0",
                  "versionType": "semver"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "value": "This issue was reported to HashiCorp by Juan Pablo Martinez Kuhn of Coinspect."
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003eThe 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\u0027s MCP session ID to have their tool calls executed using that user\u0027s Terraform credentials. This vulnerability, CVE-2026-16496, is fixed in terraform-mcp-server 1.1.0.\u003c/p\u003e\u003cbr/\u003e"
                }
              ],
              "value": "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\u0027s MCP session ID to have their tool calls executed using that user\u0027s Terraform credentials. This vulnerability, CVE-2026-16496, is fixed in terraform-mcp-server 1.1.0."
            }
          ],
          "impacts": [
            {
              "capecId": "CAPEC-60",
              "descriptions": [
                {
                  "lang": "en",
                  "value": "CAPEC-60: Reusing Session IDs (Session Replay)"
                }
              ]
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 8.9,
                "baseSeverity": "HIGH",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L",
                "version": "3.1"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-384",
                  "description": "CWE-384: Session Fixation",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-07-28T17:57:36.795Z",
            "orgId": "67fedba0-ff2e-4543-ba5b-aa93e87718cc",
            "shortName": "HashiCorp"
          },
          "references": [
            {
              "url": "https://discuss.hashicorp.com/t/hcsec-2026-23-multiple-vulnerabilities-impacting-hashicorp-terraform-mcp-server/77606"
            }
          ],
          "source": {
            "advisory": "HCSEC-2026-23",
            "discovery": "EXTERNAL"
          },
          "title": "terraform-mcp-server vulnerable to cross-user credential inheritance if an MCP session ID is obtained by another user"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "67fedba0-ff2e-4543-ba5b-aa93e87718cc",
        "assignerShortName": "HashiCorp",
        "cveId": "CVE-2026-16496",
        "datePublished": "2026-07-28T17:57:36.795Z",
        "dateReserved": "2026-07-21T16:53:07.388Z",
        "dateUpdated": "2026-07-28T18:43:58.385Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.