CVE-2026-67429 affects Flyto2 Core, an execution kernel for automation and AI-agent workflows. Prior to version 2.26.6, the image.download and related file-writing modules use a caller-controlled output_dir parameter instead of the secure validate_path_with_env_config function and its FLYTO_SANDBOX_DIR confinement mechanism. This flaw allows an attacker to control response bytes and write them to arbitrary filesystem paths accessible by the process, effectively enabling unauthorized file writes outside the intended sandbox. The vulnerability is classified as a path traversal or arbitrary file write issue. It has been patched in version 2.26.6 of Flyto2 Core. Users are strongly advised to upgrade to the fixed version immediately to mitigate risk.