GHSA-33qf-q99x-wpm8
MEDIUMGHSA-33qf-q99x-wpm8 is a medium-severity (CVSS 5.6) remote code execution vulnerability in homeassistant-cli. O3 Security confirms whether GHSA-33qf-q99x-wpm8 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Home Assistant Command-line Interface: Handling of user-supplied Jinja2 templates
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
homeassistant-cliReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Up to 1.0.0 of home-assitant-cli (or hass-cli for short) 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.
E. g., it was possible to render a template with hass-cli template bad-template.j2 --local that contained entries like
{%- set b = environ.__globals__['__builtins__'] -%}
{%- set os = b['__import__']('os') -%}
{%- set bio = b['__import__']('builtins') -%}
...
or other malicious Jinja2 expressions. This can lead to arbitrary code execution on the local machine.
In a two step process an adversary could trick/convince an user to download third-party templates which contain harmful code (e. g., perform data manipulation or establish a remote shell) then to render those templates unchecked/reviewed/verified with --local.
The issue only affect the local machine and not a remote Home Assistant instance. It also requires user interventions.
Patches
1.0.0 uses ImmutableSandboxedEnvironment and restricts the usage of environment variables.
Workarounds
Evaluate the Jninja2 templates manually or tool-based before rendering with hass-cli.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | homeassistant-cli | all versions | 1.0.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for homeassistant-cli. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update homeassistant-cli to 1.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-33qf-q99x-wpm8 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-33qf-q99x-wpm8 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-33qf-q99x-wpm8. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-33qf-q99x-wpm8 in your dependencies?
O3 detects GHSA-33qf-q99x-wpm8 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.