CVE-2026-58659: PyTorch Lightning Arbitrary Code Execution via _instantiator Hyperparameter
PyTorch Lightning through 2.6.5, fixed in commit d710d68, contains a remote code execution vulnerability in the loadstate function that imports and executes attacker-controlled module names from checkpoint instantiator hyperparameters. Attackers can craft malicious checkpoint files that bypass weightsonly=True protections to execute arbitrary code when LightningModule.loadfromcheckpoint is called.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
PyTorch Lightningto a version that resolves this vulnerability.Fixed in 2.6.5Patch d710d68 - Compensating control
Avoid calling LightningModule.load_from_checkpoint on untrusted checkpoint files until the vulnerable version is fixed.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-58659?
CVE-2026-58659 has a severity rating of 8.4 on the CVSS scale, indicating a high risk.
How do I fix CVE-2026-58659?
To remediate CVE-2026-58659, upgrade to PyTorch Lightning version 2.6.6 or later.
What type of vulnerability is CVE-2026-58659?
CVE-2026-58659 is classified as a remote code execution vulnerability.
What can happen if CVE-2026-58659 is exploited?
An attacker exploiting CVE-2026-58659 can execute arbitrary code on a victim's system.
Which versions of PyTorch Lightning are affected by CVE-2026-58659?
CVE-2026-58659 affects PyTorch Lightning versions up to and including 2.6.5.