CVE-2026-78205

Description

BentoML's 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.

CVSS Vector

References

• https://github.com/bentoml/BentoML
• https://github.com/bentoml/BentoML/blob/v1.4.39/src/bentoml/_internal/utils/uri.py#L89-L96
• https://github.com/bentoml/BentoML/issues/5644
• https://www.vulncheck.com/advisories/bentoml-through-server-side-request-forgery-via-unfiltered-rfc-6598-shared-address-space