CyberSecBulletin
CVE-2026-106440NVD status: Awaiting Analysis

hydra: Use of Externally-Controlled Input to Select Classes or Code

Published Updated By the CyberSecBulletin desk

CVE-2026-106440 is a high-severity use of externally-controlled input to select classes or code vulnerability in hydra from Hydra-ecosystem, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected hydra versions: >= 1.2.0, < 1.3.0; >= 1.4.0.dev4, < 1.4.0.dev10. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.27% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of hydra you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
Hydra-ecosystemhydra>= 1.2.0, < 1.3.0; >= 1.4.0.dev4, < 1.4.0.dev10Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA (github.com).

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use of Externally-Controlled Input to Select Classes or Code

The product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.

How developers prevent this class of flaw

  • Refactor your code to avoid using reflection.
  • Do not use user-controlled inputs to select and load classes or code.
  • Apply strict input validation by using allowlists or indirect selection to ensure that the user is only selecting allowable classes or code.

More Use of Externally-Controlled Input to Select Classes or Code vulnerabilities (CWE-470)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in hydra

All hydra vulnerabilities

Recent Use of Externally-Controlled Input to Select Classes or Code vulnerabilities

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