CVE-2026-40602: hass-cli: Handling of user-supplied Jinja2 templates

Severity: medium (CVSS 5.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-21 · updated 2026-10-26
Weakness: CWE-94

Description

The Home Assistant Command-line interface (hass-cli) is a command-line tool for Home Assistant. Up to 1.0.0 of home-assitant-cli an unrestricted environment was used to handle Jninja2 templates instead of a sandboxed one. The user-supplied input within Jinja2 templates was rendered locally with no restrictions. This gave users access to Python's internals and extended the scope of templating beyond the intended usage. This vulnerability is fixed in 1.0.0.

Affected products

home-assistant-ecosystem home-assistant-cli: before 1.0.0 — fixed in 1.0.0

How to fix

Upgrade to a fixed version: home-assistant-ecosystem home-assistant-cli 1.0.0. Check the vendor advisory for mitigations.

References

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