# 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.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Aug 2026
- **Updated:** 24 Aug 2026
- **Also known as:** GHSA-x8r7-g3fv-cf37

## 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 (Server-Side Request Forgery)

## 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.

## Is CVE-2026-78205 being exploited?

There is no known exploitation of CVE-2026-78205 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78205 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-78205 in the wild and no public exploit code.

Affected product: BentoML. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-78205/ (Markdown: https://insights.sbomify.com/CVE-2026-78205/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78205
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78205
- OSV: https://osv.dev/vulnerability/CVE-2026-78205

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78205/
Summaries are generated and may contain mistakes; the official description above is the record.