PyTorch Lightning load_from_checkpoint has an insecure checkpoint deserialization
PyTorch-Lightning versions 2.6.0 and earlier contain an insecure deserialization vulnerability (CWE-502) in the checkpoint loading mechanism. The LightningModule.load_from_checkpoint() method, which is commonly used to load saved model states, internally calls torch.load() without setting the security-restrictive weights_only=True parameter. This default behavior allows the deserialization of arbitrary Python objects via the Pickle module. A remote attacker can exploit this by providing a maliciously crafted checkpoint file, leading to arbitrary code execution on the victim's system when the file is loaded.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | lightning | <= 2.6.0 | no fix |
| Python (PyPI) | pytorch-lightning | <= 2.6.0 | no fix |
References
- CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-502- Platform
- Python (PyPI)
- Package
lightning, pytorch-lightning- Disclosed
- 12.05.2026
- Updated
- 11.10.2026 15:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-3043 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-75m9-98v2-hjpm - CC BY 4.0
OSV / GitHub Advisory Database - PYSEC-2026-3972 - PyPA Advisory Database; CC BY 4.0
Vulnerability history: pytorch-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 load_from_checkpoint has an insecure checkpoint deserialization this entry
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