Hydra instantiate target blacklist bypasses permit code executionGHSA-rqx7-p7vv-w7hr
HIGHFix: hydra-ecosystem/hydra#3412GHSA-rqx7-p7vv-w7hr is a high-severity (CVSS 7.8) CWE-184 vulnerability in hydra-core. A fix is available for hydra-core — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-rqx7-p7vv-w7hr.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-rqx7-p7vv-w7hr by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
hydra-core🐍hydra-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Hydra's instantiate() API resolves and invokes Python callables named by the _target_ field in configuration. The target blacklist introduced for CVE-2026-68508 was incomplete.
Representative bypasses included execution wrappers such as timeit.timeit, executable deserialization through pickle.loads, and generic dispatch or wrapper targets that obscured the effective callable. Target aliases, callable-returning helpers, and deferred dispatch could similarly bypass name-based checks.
An attacker who can cause an application to instantiate an untrusted Hydra configuration can use these gaps to execute code with the application's privileges.
Fix
Hydra 1.3.6 expands and hardens the blacklist used by the 1.3 compatibility line. It blocks the reported execution and deserialization surfaces, checks canonical callable identities and aliases, mediates callable results, and blocks generic dispatch and wrapper targets that bypass immediate target checks.
The Hydra 1.3 blacklist is a best-effort, defense-in-depth measure. It is not a complete security boundary and does not make untrusted configuration safe to instantiate.
Hydra 1.4.0.dev9 applies the same hardening and introduces the execution whitelist as the recommended primary security boundary. When a whitelist is supplied, targets are rejected unless trusted Python code authorizes them. If no whitelist is supplied, Hydra preserves legacy behavior with a deprecation warning and the blacklist as a best-effort compatibility fallback. Targets that permit configuration to select or supply executable behavior remain non-whitelistable.
Remediation
Upgrade to Hydra 1.3.6, or to Hydra 1.4.0.dev9 or later when testing the 1.4 prerelease line.
On Hydra 1.3, do not instantiate configuration from untrusted sources. On Hydra 1.4 and later, constrain untrusted configuration with a narrow execution whitelist supplied by trusted Python code.
For Hydra 1.4 execution-whitelist configuration, see: https://hydra.cc/docs/advanced/execution_whitelist/
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | hydra-core | ≥ 1.3.4&&< 1.3.6 | 1.3.6pip install --upgrade 'hydra-core==1.3.6' |
| 🐍PyPI | hydra-core | ≥ 1.4.0.dev0&&< 1.4.0.dev9 | 1.4.0.dev9pip install --upgrade 'hydra-core==1.4.0.dev9' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hydra-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update hydra-core to 1.3.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rqx7-p7vv-w7hr is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
A flaw of Important severity was found in the hydra-core Python configuration framework, which is bundled as a dependency in Red Hat AI Inference Server 3.3 and 3.4 and in Red Hat Enterprise Linux AI 3.4. Hydra's instantiate() mechanism does not properly validate the callable selected by the configuration target field…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for GHSA-rqx7-p7vv-w7hr (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat AI Inference Server 3.5 | rhaii/vllm-cuda-rhel9:1791473631 | RHSA-2026:82368 |
| Red Hat AI Inference Server 3.5 | rhaii/vllm-cpu-rhel9:1791473614 | RHSA-2026:82415 |
Frequently Asked Questions
Is GHSA-rqx7-p7vv-w7hr in your dependencies?
Find it across PyPI, including transitive dependencies.