CVE-2026-106440 hydra-ecosystem CVE debrief

Who should care

Defenders responsible for Hydra applications using the hydra-optuna-sweeper package should assess their exposure and verify the trustworthiness of their Optuna sweep configurations and command-line overrides.

Why it matters

This vulnerability allows for the execution of untrusted code in the Hydra controller process, potentially leading to arbitrary code execution with application privileges. Defenders should verify Optuna sweep configurations, review importable callables, and apply fixes to prevent exploitation.

• Execution of arbitrary code with application privileges
• Potential bypass of execution whitelist in Hydra 1.4 development releases
• Restoration of legacy blocklist as defense in depth in Hydra 1.3

Technical summary

The hydra-optuna-sweeper package is vulnerable to the execution of untrusted callables via the get_method API. This occurs because the package accepts a configuration-controlled dotted path in hydra.sweeper.custom_search_space, resolves it, and then invokes the returned callable without applying the execution policy used by instantiate() and logging configuration. The vulnerability allows for the execution of installed Python code in the Hydra controller process with the privileges of the application. Defenders should prioritize verifying the Optuna sweep configuration and command-line overrides, ensuring that only trusted code is executed. They should also review the application's environment for importable [

Defensive priority

Defenders should prioritize verifying the Optuna sweep configuration and command-line overrides, ensuring that only trusted code is executed. They should also review the application's environment for importable callables that could be exploited.

Recommended defensive actions

• Verify Optuna sweep configuration and command-line overrides for trustworthiness
• Review the application's environment for importable callables that could be exploited
• Apply the fix by resolving the configured callback through hydra.utils.instantiate() as a partial callable
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The vulnerability is confirmed in Hydra 1.4 development releases and 1.3 versions prior to 1.3.7. The fix involves resolving the configured callback through hydra.utils.instantiate() as a partial callable.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.