Cyber Resilience

CVE-2025-27520

RCE in Bentoml 1.3.4 – 1.4.2

Published
04 April 2025
Modified
27 June 2025
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.36 98th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2025-27520 is a critical-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Bentoml Bentoml. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

This vulnerability is AI-related — categorised as NLP and Transformers; in the Supply Chain and Deployment risk domain.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

BentoML is a Python library for building online serving systems optimized for AI applications and model inference. CVE-2025-27520 is a remote code execution vulnerability caused by insecure deserialization in version 1.4.2, residing in an unsafe code segment within serde.py. The flaw carries a CVSS score of 9.8 and is categorized under CWE-502.

Any unauthenticated remote attacker can exploit the issue over the network to execute arbitrary code on the server with no user interaction required, achieving full confidentiality, integrity, and availability impact.

The vulnerability is fixed in release 1.4.3, as noted in the project's GitHub security advisory GHSA-33xw-247w-6hmc and the associated commit that addresses the deserialization logic.

BentoML's focus on AI model serving makes the flaw particularly relevant to machine-learning infrastructure. The associated EPSS score reached a peak of 0.8735 with a current value of 0.7576, indicating notable post-disclosure exploitation interest.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

AI Security AnalysisAI

AI Category
NLP and Transformers
Risk Domain
Supply Chain and Deployment
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: ai, bentoml

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-32375Same product: Bentoml Bentoml
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CVE-2026-35043Same product: Bentoml Bentoml
CVE-2026-44345Same product: Bentoml Bentoml
CVE-2026-24123Same product: Bentoml Bentoml
CVE-2026-33744Same product: Bentoml Bentoml
CVE-2026-44346Same product: Bentoml Bentoml
CVE-2026-35044Same product: Bentoml Bentoml
CVE-2026-40610Same product: Bentoml Bentoml
CVE-2026-27905Same product: Bentoml Bentoml

Affected Assets

bentoml
bentoml
1.3.4 — 1.4.2

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can uncover deserialization flaws before deployment.

Input validation directly stops deserialization of untrusted data by ensuring inputs are valid before processing.

Engineering principles such as safe deserialization and input sanitization structurally prevent the weakness from being introduced.

Integrity verification tools can detect malformed or tampered serialized data after the fact.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-02 none match
prevents

PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing includes validation of deserialization routines and the use of untrusted data, reducing the likelihood that unsafe object reconstruction will be deployed.

prevents

Requiring vetted libraries, regular updates and SAST before release reduces the likelihood that deserialization logic will accept and act on attacker-controlled serialized objects.

finds

Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.

none

Mandatory malware scanning of data received over networks or storage media intercepts malicious serialized payloads before they are deserialized by the target application.

References