BentoML up to 1.4.37 generate.py generate_containerfile special elements used in a template engine

Summaryinfo

A vulnerability was found in BentoML up to 1.4.37. It has been classified as critical. Affected by this vulnerability is the function generate_containerfile of the file src/bentoml/_internal/container/generate.py. The manipulation leads to improper neutralization of special elements used in a template engine. This vulnerability is traded as CVE-2026-35044. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, has been found in BentoML up to 1.4.37. This issue affects the function generate_containerfile of the file src/bentoml/_internal/container/generate.py. The manipulation with an unknown input leads to a improper neutralization of special elements used in a template engine vulnerability. Using CWE to declare the problem leads to CWE-1336. The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

BentoML is a Python library for building online serving systems optimized for AI apps and model inference. Prior to 1.4.38, the Dockerfile generation function generate_containerfile() in src/bentoml/_internal/container/generate.py uses an unsandboxed jinja2.Environment with the jinja2.ext.do extension to render user-provided dockerfile_template files. When a victim imports a malicious bento archive and runs bentoml containerize, attacker-controlled Jinja2 template code executes arbitrary Python directly on the host machine, bypassing all container isolation. This vulnerability is fixed in 1.4.38.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-35044 since 03/31/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1221 according to MITRE ATT&CK.

Upgrading to version 1.4.38 eliminates this vulnerability.

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Productinfo

Name

• BentoML

Version

• 1.4.0
• 1.4.1
• 1.4.2
• 1.4.3
• 1.4.4
• 1.4.5
• 1.4.6
• 1.4.7
• 1.4.8
• 1.4.9
• 1.4.10
• 1.4.11
• 1.4.12
• 1.4.13
• 1.4.14
• 1.4.15
• 1.4.16
• 1.4.17
• 1.4.18
• 1.4.19
• 1.4.20
• 1.4.21
• 1.4.22
• 1.4.23
• 1.4.24
• 1.4.25
• 1.4.26
• 1.4.27
• 1.4.28
• 1.4.29
• 1.4.30
• 1.4.31
• 1.4.32
• 1.4.33
• 1.4.34
• 1.4.35
• 1.4.36
• 1.4.37

Website

• Product: https://github.com/bentoml/BentoML/

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