CVE-2026-106440 Hydra: Optuna custom_search_space can resolve and execute untrusted callables via get_method
Attackers controlling Optuna sweep configurations can execute arbitrary Python code via untrusted callables in Hydra's custom search space.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-106440?
CVE-2026-106440 is a high-severity code injection vulnerability in hydra-ecosystem hydra, published on 6 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
Hydra is a framework for elegantly configuring complex applications. From 1.2.0 until 1.3.0 and 1.4.0.dev10, the hydra-optuna-sweeper package accepts a configuration-controlled dotted path in hydra.sweeper.custom_search_space, resolves it with hydra.utils.get_method(), and later invokes the returned callable in the Hydra controller process. Because get_method() is a trusted-input lookup helper and does not apply the execution policy used by instantiate(), an attacker who controls Optuna sweep configuration or command-line overrides can select importable Python code for execution with the application's privileges, including bypassing a trusted execution whitelist on affected Hydra 1.4 development releases. This issue is fixed in versions 1.3.0 and 1.4.0.dev10.
Weakness: CWE-470
Which versions are affected by CVE-2026-106440?
5 open source packages ship an affected version, including hydra-optuna-sweeper.
| Package | Affected | Fixed in |
|---|---|---|
hydra-optuna-sweeper PyPI | From 1.2.0 | 1.3.0, 1.4.0.dev10 |
hydra-optuna-sweeper PyPI | From 1.2.0 | 1.3.0 |
hydra-optuna-sweeper PyPI | From 1.2.0 | 1.3.0 |
hydra-optuna-sweeper PyPI | From 1.4.0.dev4 | 1.4.0.dev10 |
hydra-optuna-sweeper PyPI | From 1.4.0.dev4 | 1.4.0.dev10 |
How do I fix CVE-2026-106440?
Upgrade hydra-optuna-sweeper to a fixed version for your release line: 1.3.0 or 1.4.0.dev10.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-106440 being exploited?
There is no known exploitation of CVE-2026-106440 in the wild and no public exploit code.
Sources
Also known as GHSA-5jjj-9xc3-rm56, PYSEC-2026-4224.