PyTorch-Lightning up to 2.6.0 Pickle LightningModule.load_from_checkpoint deserialization

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability was found in PyTorch-Lightning up to 2.6.0. It has been declared as critical. This affects the function LightningModule.load_from_checkpoint of the component Pickle Module. Such manipulation leads to deserialization. This vulnerability is listed as CVE-2026-31221. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in PyTorch-Lightning up to 2.6.0. It has been rated as critical. Affected by this issue is the function LightningModule.load_from_checkpoint of the component Pickle Module. The manipulation with an unknown input leads to a deserialization vulnerability. Using CWE to declare the problem leads to CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-31221 since 03/09/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/19/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.6
VulDB Meta Temp Score: 7.6

VulDB Base Score: 6.3
VulDB Temp Score: 6.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔒

ADP CISA Base Score: 8.8
ADP CISA Vector: 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Deserialization
CWE: CWE-502 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

03/09/2026 CVE reserved
05/12/2026 +63 days Advisory disclosed
05/12/2026 +0 days VulDB entry created
05/19/2026 +7 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Not defined

CVE: CVE-2026-31221 (🔒)
GCVE (CVE): GCVE-0-2026-31221
GCVE (VulDB): GCVE-100-363068

Entryinfo

Created: 05/12/2026 18:46
Updated: 05/19/2026 03:17
Changes: 05/12/2026 18:46 (52), 05/19/2026 03:17 (20)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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