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Compromise of PyTorch Lightning PyPi Package Versions

Critical severity GitHub Reviewed Published Apr 30, 2026 in Lightning-AI/pytorch-lightning • Updated May 7, 2026

Package

pip pytorch-lightning (pip)

Affected versions

= 2.6.2
= 2.6.3

Patched versions

None

Description

Security Advisory: Compromise of PyTorch Lightning PyPI Package Versions

Published: 2026-04-30
Last Updated: 2026-04-30

Lightning AI has identified a security incident affecting certain versions of a PyPI package.

What happened

Lightning AI has determined that one or more released versions of this package have been compromised and include malicious code.

The current investigation indicates that the affected versions have introduced functionality consistent with a credential harvesting mechanism. There is a continuing analysis the scope and behaviour of the code.

At this stage, the root cause of the compromise is still under investigation.

What versions are affected

Lightning AI is currently working to confirm the exact set of impacted versions.

The following versions are determined as affected, and developers should delete them from their systems:

  • 2.6.2
  • 2.6.3

Lightning AI will update this advisory if the versions impacted by this vulnerability change.

What you should do immediately

If developers have installed or are running any potentially affected versions on their application:

  • Assume the environment may be compromised
  • Immediately rotate all credentials and secrets that may have been exposed, including:
    • API keys
    • Access tokens
    • SSH keys
    • Service account credentials
  • Rebuild affected systems from a known clean state
  • Pin PyTorch Lightning to version 2.6.1
  • Review logs for any suspicious or unauthorised activity

Actions Lightning AI has taken

Ongoing investigation

Lightning AI is actively working to:

  • Identify the exact mechanism of compromise
  • Confirm the full set of affected versions
  • Determine the behaviour and impact of the malicious code
  • Assess any downstream impact to users

Lightning AI will provide updates as soon as more information becomes available.

Commitment to transparency

Lightning AI takes the security of users and the integrity of the software supply chain extremely seriously.

Lightning AI will continue to share timely and accurate updates as the investigation progresses.

Contact

If there are any questions or if there are concerns that a consuming project may be impacted, please send an email to:

security@lightning.ai

References

@brahman81 brahman81 published to Lightning-AI/pytorch-lightning Apr 30, 2026
Published to the GitHub Advisory Database May 7, 2026
Reviewed May 7, 2026
Last updated May 7, 2026

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS score

Weaknesses

Embedded Malicious Code

The product contains code that appears to be malicious in nature. Learn more on MITRE.

CVE ID

CVE-2026-44484

GHSA ID

GHSA-w37p-236h-pfx3

Source code

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