CVE-2026-31221: PyTorch-Lightning versions 2.6.0 and earlier contain an insecure deserialization vulnerability (CWE-502) in th

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HIGH 7.8UPGRADE

CVE-2026-31221 is a high-severity flaw (CVSS 7.8) affecting pytorch lightning. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 remo

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-502
Published	2026-05-12
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: lightningai

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-12 16:16 UTCPublished CVE record published
2026-06-17 10:33 UTCUpdated Record last modified

lightningai pytorch lightning UPGRADE

Affected: <= 2.6.0

Fixed in: newer than 2.6.0

Safe to downgrade to: no unaffected older release

1. Check installed version

pip show pytorch-lightning

2. UPGRADE to newer than 2.6.0

pip install --upgrade "pytorch-lightning>2.6.0"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-31221?

pytorch lightning: upgrade to newer than 2.6.0. Exact commands for each OS are on this page.

Is CVE-2026-31221 being exploited?

CVE-2026-31221 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-31221 affect?

CVE-2026-31221 affects pytorch lightning. Severity is high (CVSS 7.8). 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 stat

How urgent is CVE-2026-31221?

Priority 40/100. High severity; Public exploit reference

Software pages

Python vulnerabilities · PyTorch vulnerabilities · Check Point vulnerabilities

Related CVEs

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CVE-2026-44484 CRITICAL 9.8 DOWNGRADE PyTorch Lightning is a deep learning framework to pretrain and finetune AI models

References

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