CVE-2026-106439

Hydra: Mutable instantiate policy sets allow target blocklist bypass

Published Oct 6, 2026 CVSS 4.0 · 8.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-mwj6-rfh8-7qf4 Hydra: Mutable instantiate policy sets allow target blocklist bypass
History
Type Values Removed Values Added
First Time appeared Hydra-ecosystem
Hydra-ecosystem hydra
Vendors & Products Hydra-ecosystem
Hydra-ecosystem hydra
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

threat_severity

Important

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Hydra: Mutable instantiate policy sets allow target blocklist bypass
Weaknesses CWE-470
CWE-693
References
Metrics cvssV4_0

{'score': 8.5, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 6, 2026, 7:48 PM
Reserved
Oct 6, 2026, 4:49 PM
Status
Awaiting Analysis
Published
Oct 6, 2026, 7:18 PM
Modified
Oct 6, 2026, 8:17 PM
Severity
Important
Public date
Oct 6, 2026, 6:49 PM