CVE-2026-58659: PyTorch Lightning Arbitrary Code Execution via _instantiator Hyperparameter

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-07-15 · updated 2026-10-24
Weakness: CWE-470

Description

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 products

lightning-ai/pytorch-lightning: through 2.6.5

References

https://github.com/Lightning-AI/pytorch-lightning/commit/d710d689510d50e800f53b3cd773cbca20b1f86f
https://github.com/Lightning-AI/pytorch-lightning/issues/21822
https://github.com/Lightning-AI/pytorch-lightning/pull/21832
https://www.vulncheck.com/advisories/pytorch-lightning-arbitrary-code-execution-via-instantiator-hyperparameter

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