PyTorch Lightning allows arbitrary code execution through checkpoint _instantiator hyperparameters
PyTorch Lightning through 2.6.5, fixed in commit d710d68, contains a remote code execution vulnerability in the _load_state function that imports and executes attacker-controlled module names from checkpoint _instantiator hyperparameters. Attackers can craft malicious checkpoint files that bypass weights_only=True protections to execute arbitrary code when LightningModule.load_from_checkpoint is called.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | lightning | < 2.6.6 | 2.6.6 |
| Python (PyPI) | pytorch-lightning | < 2.6.6 | 2.6.6 |
References
- https://github.com/Lightning-AI/pytorch-lightning/issues/21822
- https://github.com/Lightning-AI/pytorch-lightning/commit/d710d689510d50e800f53b3cd773cbca20b1f86f
- https://github.com/Lightning-AI/pytorch-lightning/pull/21832
- https://www.vulncheck.com/advisories/pytorch-lightning-arbitrary-code-execution-via-instantiator-hyperparameter
- https://github.com/Lightning-AI/pytorch-lightning/releases/tag/2.6.6
- https://github.com/advisories/GHSA-qqmf-gpg7-g8gw
- https://nvd.nist.gov/vuln/detail/CVE-2026-58659
- https://github.com/Lightning-AI/pytorch-lightning
- https://github.com/pypa/advisory-database/tree/main/vulns/lightning/PYSEC-2026-3624.yaml
- https://github.com/pypa/advisory-database/tree/main/vulns/pytorch-lightning/PYSEC-2026-3967.yaml
- CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-470- Platform
- Python (PyPI)
- Package
lightning, pytorch-lightning- Disclosed
- 15.07.2026
- Updated
- 11.10.2026 15:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-3624 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - PYSEC-2026-3967 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-qqmf-gpg7-g8gw - CC BY 4.0
Vulnerability history: lightning
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 9
- First → latest
- 12.2021 07.2026
- Without a fix
- 2
- Exploited in attacks
- 0
Severity breakdown
- Critical 5
- High 4
Disclosures per year
- 2021: 1
- 2022: 1
- 2023: 0
- 2024: 2
- 2025: 2
- 2026: 3
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PyTorch Lightning allows arbitrary code execution through checkpoint _instantiator hyperparameters this entry
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