CVE-2025-27520 BentoML Allows Remote Code Execution (RCE) via Insecure Deserialization
Unauthenticated attackers can execute arbitrary code on servers using BentoML due to insecure deserialization in the serde module.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-27520?
CVE-2025-27520 is a critical unsafe deserialization vulnerability in BentoML, published on 4 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-502
Which versions are affected by CVE-2025-27520?
3 open source packages ship an affected version, including bentoml. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
bentoml PyPI | From 1.3.4 | 1.4.3 |
bentoml PyPI | From 1.3.4 | 1.4.3 |
bentoml PyPI | From 1.3.4 | 1.4.3 |
Products include Bentoml Bentoml.
How do I fix CVE-2025-27520?
Upgrade bentoml to 1.4.3 or later.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2025-27520 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-27520 exists.
Public exploit code: 1 Metasploit module and 3 proofs of concept on GitHub.
Other vulnerabilities in BentoML
- CVE-2025-54381 BentoML is Vulnerable to an SSRF Attack Through File Upload Processing
- CVE-2025-32375 Insecure Deserialization leads to RCE in BentoML's runner server
- CVE-2026-44345 BentoML: Dockerfile command injection via docker.base_image
- CVE-2026-44346 BentoML: Dockerfile command injection via envs[*].name in bentofile.yaml
- CVE-2026-35044 BentoML has a Server-Side Template Injection via unsandboxed Jinja2 Environment in Dockerfile generation
Sources
Also known as GHSA-33xw-247w-6hmc, PYSEC-2026-294.