BentoML vulnerabilities

BentoML through 1.4.39 contains a Dockerfile instruction injection vulnerability allowing attackers to add arbitrary build instructions by embedding newlines in docker.env mapping keys rendered by the legacy base.j2 template. A crafted bentofile.yaml or imported bento archive can cause bentoml containerize to execute injected RUN instructions during docker build, accessing build secrets and poisoning images.

In BentoML, the outbound connection safeguard (make_safe_connect in _internal/utils/uri.py) blocks private, loopback, and link-local IP addresses but fails to reject the RFC 6598 shared address space (100.64.0.0/10, CGNAT). In versions 1.4.19 through 1.4.39, an unauthenticated attacker can supply URLs pointing to that range via multipart file handling (MultipartSerde.ensure_file) or JSON request parsing (JSONSerde.parse_request), causing the server to make outbound requests to internal hosts on CGNAT networks (Server-Side Request Forgery). This is an incomplete fix for CVE-2025-54381.

In BentoML versions 1.4.38 and prior, the build packaging workflow follows attacker-controlled symlinks inside the build context and copies the referenced file contents into the generated Bento artifact. An attacker can place a symlink pointing to a sensitive local file, which gets packaged into the Bento.