Hydra: Optuna custom_search_space can resolve and execute untrusted callables via get_method

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.8 · CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-106440: 0.27% estimated exploitation activity in the next 30 days; percentile 19.36 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary hydra-optuna-sweeper accepted a configuration-controlled dotted path in hydra.sweeper.customsearchspace, resolved it with the lower-level hydra.utils.getmethod() API, and later invoked the returned callable. Hydra's object-lookup helpers intentionally trust their input and do not apply the execution policy used by instantiate() and logging configuration. As a result, untrusted Optuna multirun configuration could select installed Python code for execution in the Hydra controller process. Impact Exploitation requires control of an application's Optuna sweep configuration or command-line overrides and an importable callable in the application's environment. Selected code runs with the privileges of the application. On affected Hydra 1.4 development releases, this path bypasses an execution whitelist provided by trusted application code. Hydra 1.3 has no execution-whitelist security boundary; there, the same change restores the legacy blocklist as defense in depth. Fix The Optuna…

Published by the source

7 Oct 2026, 20:24 UTC

Last modified by the source

7 Oct 2026, 20:24 UTC

Source last checked

26 Oct 2026, 13:55 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-5jjj-9xc3-rm56

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# Patch Next advisory brief: CVE-2026-106440

Advisory: Hydra: Optuna custom_search_space can resolve and execute untrusted callables via get_method
IDs: CVE-2026-106440, GHSA-5jjj-9xc3-rm56
Record: https://patchnext.com/advisories/cve-2026-106440 (revision 1, source checked 26 Oct 2026, 13:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: hydra-optuna-sweeper 1.4.0.dev10, 1.3.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI hydra-optuna-sweeper: affected >= 1.2.0, < 1.3.0; >= 1.4.0.dev4, < 1.4.0.dev10; fixed in 1.3.0, 1.4.0.dev10

## Suggested inspection (read-only)
- `python -m pip show hydra-optuna-sweeper`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on hydra-optuna-sweeper.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-5jjj-9xc3-rm56 (GitHub-reviewed advisory GHSA-5jjj-9xc3-rm56 lists affected ranges: PyPI hydra-optuna-sweeper >=1.2.0 =1.4.0.dev4 <1.4.0.dev10)

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