CVE-2026-78205 BentoML 1.4.19 through 1.4.39 Server-Side Request Forgery via Unfiltered RFC 6598 Shared Address Space
Unauthenticated attackers can exploit BentoML to perform Server-Side Request Forgery against internal CGNAT networks by bypassing IP filtering safeguards.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-78205?
CVE-2026-78205 is a medium-severity server-side request forgery vulnerability in BentoML, published on 24 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-918
Which versions are affected by CVE-2026-78205?
How do I fix CVE-2026-78205?
No fix has been published for CVE-2026-78205 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-78205 being exploited?
There is no known exploitation of CVE-2026-78205 in the wild and no public exploit code.
Sources
Also known as GHSA-x8r7-g3fv-cf37.