CVE-2026-106439: high-severity vulnerability in hydra-ecosystem hydra
Hydra: Mutable instantiate policy sets allow target blocklist bypass
Published
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.5epss 0.5%
exploitation probability
0.5%top 62% of all CVEs
observed exploitation
nono source reports it
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:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
hydra-ecosystem · hydraRelated CVEs — hydra-ecosystem hydra
In the same product, most dangerous first.
CVE-2026-106440HIGHHydra: Optuna custom_search_space can resolve and execute untrusted callables via get_methodEPSS 0.3%CVE-2026-106441HIGHHydra logging configuration permits unsafe callable resolutionEPSS 0.2%CVE-2026-106442HIGHHydra instantiate target blacklist bypasses permit code executionEPSS 0.2%
References
https://github.com/hydra-ecosystem/hydra/commit/0dd18084589a3d3e577d1f1a8a48fb485c94a5e6https://github.com/hydra-ecosystem/hydra/commit/4720dfca2bde27fa140ec287a05709668fbdf168https://github.com/hydra-ecosystem/hydra/releases/tag/v1.3.7https://github.com/hydra-ecosystem/hydra/security/advisories/GHSA-mwj6-rfh8-7qf4