High 8.5Published Oct 6, 2026

CVE-2026-106439Hydra: Mutable instantiate policy sets allow target blocklist bypass

Updated under an hour ago (2026-10-19 08:23 UTC)

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It affects hydra-ecosystem hydra. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.46%, higher than 39% of scored CVEs.

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Exploited in the last 30 days

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.

CVSS: 8.5 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-470, CWE-693
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.46% (percentile 39)
Assigned by: GitHub_M
NVD analysis: Awaiting Analysis
Record last updated: Oct 6, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

hydra-ecosystem hydra hydra_ecosystem:hydra (from the name)	from 1.3.4, < 1.3.7; from 1.4.0.dev4, < 1.4.0.dev10	CNA record

References

https://github.com/hydra-ecosystem/hydra/security/advisories/GHSA-mwj6-rfh8-7qf4x-refsource-confirm
https://github.com/hydra-ecosystem/hydra/commit/0dd18084589a3d3e577d1f1a8a48fb485c94a5e6x-refsource-misc
https://github.com/hydra-ecosystem/hydra/commit/4720dfca2bde27fa140ec287a05709668fbdf168x-refsource-misc
https://github.com/hydra-ecosystem/hydra/releases/tag/v1.3.7x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.