CVE-2026-106439 · GHSA-mwj6-rfh8-7qf4
Hydra: Mutable instantiate policy sets allow target blocklist bypass
- Risk score
- 64/100
- CVSS
- 8.5 v4.0
- Exploit chance (30 days)
- 0.5%
- Published
- 6 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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.tar…
- Affected
- hydra-core (pip) >= 1.3.4, < 1.3.7; hydra-core (pip) >= 1.4.0.dev4, < 1.4.0.dev10
- Fix
- Upgrade hydra-core to 1.3.7 or 1.4.0.dev10 (whichever matches your release line) or later.
- Exploitation
- No known exploitation
Story map
At a glance
hydra-core: Amber, patch this week. 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.tar…
The flaws
- CVE-2026-106439: Hydra: Mutable instantiate policy sets allow target blocklist bypass (CVSS 8.5 · EPSS 0%)
- CVE-2026-106441: Hydra logging configuration permits unsafe callable resolution (CVSS 7.8 · EPSS 0%)
- CVE-2026-106442: Hydra instantiate target blacklist bypasses permit code execution (CVSS 7.8 · EPSS 0%)
The fix
Upgrade hydra-core: 1.3.7 · 1.4.0 · 1.3.6 or later on your release line
Who is exposed: hydra-core (pip) >= 1.3.4, < 1.3.7; hydra-core (pip) >= 1.4.0.dev4, < 1.4.0.dev10
Where it stands
- No known exploitation
Connects to
- Same weakness: CWE-470 (CWE-470). 26 other warnings in 30 days
Why it is Amber
- CVSS 8.5 high
- On your watchlist: PyPI
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| hydra-core | pip | >= 1.3.4, < 1.3.7 | 1.3.7 |
| hydra-core | pip | >= 1.4.0.dev4, < 1.4.0.dev10 | 1.4.0.dev10 |
References
- https://github.com/advisories/GHSA-mwj6-rfh8-7qf4
- https://github.com/hydra-ecosystem/hydra/security/advisories/GHSA-mwj6-rfh8-7qf4
- https://nvd.nist.gov/vuln/detail/CVE-2026-106439
- https://github.com/hydra-ecosystem/hydra/commit/0dd18084589a3d3e577d1f1a8a48fb485c94a5e6
- https://github.com/hydra-ecosystem/hydra/commit/4720dfca2bde27fa140ec287a05709668fbdf168
- https://github.com/hydra-ecosystem/hydra/releases/tag/v1.3.7
- https://github.com/advisories/GHSA-mwj6-rfh8-7qf4
Original 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.
Last activity 6 Oct 2026. Patch Forecast updates every hour.