Description
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 products
lightningai: pytorch lightning
References2
- www.notion.so/CVE-2026-31221-35d1e1393188815f8db7c4fd08076639 ExploitThird Party Advisory
- github.com/Lightning-AI/pytorch-lightning Product
Metrics
- CVSS 3.1
-
7.8
HIGH
Score source: NVD
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 33 · as of 14 November 2026
- CWE
- CWE-502
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.