CVE-2026-120308

Name of the Vulnerable Software and Affected Versions Beam Cloud Beta9 Gateway versions prior to 0.1.776 Beam Cloud Beta9 Worker versions prior to 0.1.756

Description An issue exists where a tenant with a workspace token can attach a volume when deploying a function, endpoint, or task queue. The gateway constructs the host path by joining the shared volumes root, the workspace name, and the volume identifier from the stub configuration without verifying if the workspace owns the specified volume. By using parent-directory segments in the volume identifier, a path traversal occurs, collapsing the joined path to the worker's filesystem root. This allows the worker to bind-mount the path into the sandbox with read-write access, unless explicitly marked read-only, enabling a tenant to read and write the worker's files and access volumes belonging to other tenants stored on the same machine.

Recommendations Update Beam Cloud Beta9 Gateway to version 0.1.776 or later. Update Beam Cloud Beta9 Worker to version 0.1.756 or later. Restrict untrusted volume attachment as a mitigation measure.