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[ CVE-2026-106439 · Published 6 Oct 2026 ]

Hydra: Mutable instantiate policy sets allow target blocklist bypass

CVSS 8.5 EPSS <1%Fix available

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

Hydra is a framework for elegantly configuring complex applications. From 1.3.4 until 1.3.7 and 1.4.0.dev10, Hydra stores legacy instantiate target blocklists and related execution-policy collections in mutable module-level state. An attacker who controls multiple sibling target entries can resolve hydra._internal.target_policy.UNCONTROLLED_EXECUTION_TARGETS.discard through instantiate(), remove a denied target, and then invoke that target because sibling nodes are processed in insertion order against the same modified policy. The mutation persists in process-global state and can enable code execution with the application's privileges, while a narrow execution whitelist supplied by trusted Python code is not bypassed by the reported direct mutation path. This issue is fixed in versions 1.3.7 and 1.4.0.dev10.

[ Fixes ]Fixes and patches

  • hydra-core 1.3.7Fixed version · GitHub Advisories · pip package hydra-core: upgrade to 1.3.7 or later (affected >= 1.3.4, < 1.3.7)
  • hydra-core 1.4.0.dev10Fixed version · GitHub Advisories · pip package hydra-core: upgrade to 1.4.0.dev10 or later (affected >= 1.4.0.dev4, < 1.4.0.dev10)

[ Packages ]Affected open-source packages

[ References ]References