HCSEC-2026-54 - Boundary vulnerable to server-side request forgery in Vault credential store

Bulletin ID: HCSEC-2026-54 Affected Products / Versions: Boundary and Boundary Enterprise 0.21.3 up to 1.0.1; fixed in Boundary Enterprise 1.0.2 and 0.21.6. Publication Date: October 29, 2026 Summary HashiCorp Boundary and Boundary Enterprise are vulnerable to a server-side request forgery in the Vault credential store integration that may allow an authenticated user with permission to manage credential stores and credential libraries within a project to cause the Boundary controller to issue outbound requests to a network destination of the requester’s choosing and to receive the response. This may expose endpoints reachable only from the controller’s host, such as a cloud instance metadata service. This vulnerability, CVE-2026-13303, is fixed in Boundary Enterprise 1.0.2 and 0.21.6. Background Boundary brokers credentials to targets by integrating with external credential sources such as HashiCorp Vault. A Vault credential store is configured with a Vault address and token, and credential libraries reference paths that the controller requests on the user’s behalf. By design, end users do not connect to these backends directly; the controller performs the outbound request from its own network position. Details The controller did not sufficiently restrict the network destination of these outbound Vault requests. A principal authorized to create or update a Vault credential store and credential library in a project could supply configuration that directed the controller to an unintended internal address and, by influencing the response, cause the controller to follow that request to a further destination and return the result to the requester. Because the controller operates from a trusted network position, this could expose information reachable only from the controller, potentially including sensitive infrastructure endpoints, a higher level of access than the requester’s project-scoped permissions are intended to grant. Exploitation requires an authenticat…